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Raspberry-Rhubarb Slab Pie Recipe

Raspberry-Rhubarb Slab Pie Recipe

"Slab pie" is a pastry baked in a jelly-roll pan and cut in slabs like a bar cookie—or a pie bar, if you will. My grandfather was a professional baker and served pieces of slab pie to his customers back in the day. Here is my spin, featuring rhubarb and gorgeous red raspberries. —Jeanne Ambrose, Milwaukee, Wisconsin
TOTAL TIME: Prep: 30 min. + chilling Bake: 45 min. + cooling YIELD:24 servings


  • 3-1/4 cups all-purpose flour
  • 1 teaspoon salt
  • 1 cup butter
  • 3/4 cup plus 1 to 2 tablespoons 2% milk
  • 1 egg yolk
  • 2 cups sugar
  • 1/3 cup cornstarch
  • 5 cups fresh or frozen unsweetened raspberries, thawed and drained
  • 3 cups sliced fresh or frozen rhubarb, thawed and drained
  • 1-1/4 cups confectioners' sugar
  • 1/2 teaspoon vanilla extract
  • 5 to 6 teaspoons 2% milk


  • 1. In a large bowl, combine flour and salt; cut in butter until crumbly. Whisk 3/4 cup milk and egg yolk; gradually add to flour mixture, tossing with a fork until dough forms a ball. Add additional milk, 1 tablespoon at a time, if necessary.
  • 2. Divide dough in two portions so that one is slightly larger than the other; wrap each in plastic wrap. Refrigerate 1 hour or until easy to handle.
  • 3. Preheat oven to 375°. Roll out larger portion of dough between two large sheets of lightly floured waxed paper into an 18x13-in. rectangle. Transfer to an ungreased 15x10x1-in. baking pan. Press onto the bottom and up sides of pan; trim pastry to edges of pan.
  • 4. In a large bowl, combine sugar and cornstarch. Add raspberries and rhubarb; toss to coat. Spoon into pastry.
  • 5. Roll out remaining dough; place over filling. Fold bottom pastry over edge of top pastry; seal with a fork. Prick top with a fork.
  • 6. Bake 45-55 minutes or until golden brown. Cool completely on a wire rack.
  • 7. For icing, combine confectioners' sugar, vanilla and enough milk to achieve a drizzling consistency; drizzle over pie. Cut pie into squares. Yield: 2 dozen.
Editor's Note: If using frozen rhubarb, measure rhubarb while still frozen, then thaw completely. Drain in a colander, but do not press liquid out.

Recipe Note

Test Kitchen Tips

  • This pie dough can be made ahead of time and frozen. Thaw overnight in the fridge.
  • Before refrigerating or freezing pie dough, shape it into two rectangles so it's easier to roll into larger rectangles later.
  • Nutritional Facts

    1 piece: 247 calories, 8g fat (5g saturated fat), 29mg cholesterol, 159mg sodium, 42g carbohydrate (25g sugars, 2g fiber), 3g protein.

    Reviews for Raspberry-Rhubarb Slab Pie

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    MY REVIEW User ID: 1426899 253695
    Reviewed Sep. 5, 2016

    "Very good. I took it to a picnic and didn't get to bring any home. Definitely will make again.."

    cyndypetters User ID: 3725488 249567
    Reviewed Jun. 18, 2016

    "I made this with equal amounts of rhubarb and raspberries and a bit less sugar. My family and friends loved it!"

    FARIKAT User ID: 7299327 246766
    Reviewed Apr. 8, 2016

    "This was a great way to use the frozen raspberries and rhubarb that I had in the freezer. I am not the greatest pastry chef, so rolling out dough is not an easy job for me. But, I managed. I went one step further and used the food processor for the rhubarb to give it a more even consistency.

    But, I am confused as to why the oven temperature needs to be 375. In this day and age of well-insulated ovens and pans that are non-stick, I never need to use 375 and I put my oven at 350 for the allotted time and it was still slightly over-baked.
    Take it easy on the heat.

    eliot11 User ID: 8156312 241454
    Reviewed Jan. 10, 2016

    "Our family loves both raspberries and rhubarb-the combination is outstanding. I do 1 1/2 times the recipe as I use a LG jelly roll pan. Outstanding dessert"

    hchambers User ID: 7140928 228758
    Reviewed Jun. 30, 2015

    "Great dessert for a crowd. I have also made it with strawberries as well. I also reduced berries by a cup and added a cup to the rhubarb. I will definitely make this again."

    Ldkelly User ID: 5655236 227403
    Reviewed Jun. 4, 2015

    "One of only ways I will eat rhubarb. The only change that I make is I use the pie crust only on the bottom and substitute sugar cookie dough on top. It makes. Great different way of putting it together."

    cmead User ID: 1313690 227221
    Reviewed May. 31, 2015

    "I'm rhubarb rich and not willing to spend that many of my hard earned raspberries, so I use 5 c. rhubarb with 3 c. frozen strawberries. With all that cornstarch I have no problem with thickening. I will work on sealing the edges better next time. I had a mess all over the bottom of the oven. I don't remember having that problem the last time I made it. The crust is very forgiving (due to the addition of the egg yolk?). You can make it do what you want it to do without tearing, Anyway, it was a great success at the potluck. I'm glad I took a piece before I ate the rest of the meal because it was gone by the time I got back to the dessert table!"

    kittydog User ID: 1951624 226335
    Reviewed May. 14, 2015

    "The taste was wonderful, but it was difficult to seal the edges together and the juices ran out of the crust. Next time I will just make a pie."

    jallen99 User ID: 7881994 152160
    Reviewed Nov. 7, 2014

    "This is very simpler to the one that I use at Christmas. I use mincemeat and never ever come home with any left after a potluck!"

    christquest User ID: 6648138 138116
    Reviewed Oct. 1, 2014

    "I've made this several times subbing strawberries for raspberries and every time it's been a huge hit!"

    KristineChayes User ID: 1441542 152158
    Reviewed Sep. 30, 2014

    "I'd never made a slab pie before and this one turned out great. The combination of raspberries and rhubarb was delicious, and baking it in a jelly roll pan made slicing and serving simple. I am going to bake my next apple pie in this manner! Great dessert! Thank you, Jeanne Ambrose, for sharing your grandfather's tasty recipe!"

    Tami12 User ID: 7842456 198931
    Reviewed Aug. 2, 2014

    "Can't wait"

    SrSuzy User ID: 7831621 197218
    Reviewed Jul. 10, 2014

    "I would like to try this but with different fruit...any suggestions?"

    keely27 User ID: 4249986 138115
    Reviewed Jul. 5, 2014

    "Followed recipe as written and it turned out great!"

    Travale User ID: 1709114 152154
    Reviewed Jul. 2, 2014

    "This was delicious. I only had about 3 cups of raspberries, so I did 5 cups of rhubarb and the combination was perfect. The icing on top was a really nice touch."

    kaydeel User ID: 3413898 126775
    Reviewed Jun. 18, 2014

    "I really liked this after it had been refrigerated. My husband was impressed. The downside for me was handling the dough. I actually had to put it in the freezer then I could get it to roll better. Probably will make again."

    Bobbijune User ID: 7838415 197374
    Reviewed Jun. 18, 2014

    "I didn't have raspberries so substituted thawed frozen strawberries, big mistake. They were too juicy for this recipe and the crust stayed soggy. But the flavor was outstanding! Next time I'll follow the recipe using raspberries."

    cside28 User ID: 7627576 197217
    Reviewed Jun. 17, 2014

    "I made this recipe just as it was shown, it was excellent! I think next time I will use less sugar, I thought with rhubarb I would need all the sugar, but I didn't. The crust was a bear, but I hate making pie crust anyway, this was just larger, but it turned out fine."

    KAT51 User ID: 5314282 185888
    Reviewed Jun. 17, 2014

    "Was very good. Not very good at making pie crust so used one you roll out all ready made turned out great. Will for sure make again."

    kmbattles User ID: 3823980 139117
    Reviewed Jun. 17, 2014

    "It was an easy & good recipe. However, ithe quite tart. I'll add 1/2 sugar the next time."

    SVogel User ID: 5898446 197215
    Reviewed Jun. 17, 2014

    "Enjoyed this recipe very much! I used mixed frozen berries with fresh rhubarb, half the sugar and it turned out delicious!"

    LeslieH User ID: 191346 197999
    Reviewed Jun. 16, 2014

    "Very tasty! Great for a potluck or bbq"

    sewsal User ID: 2105914 126774
    Reviewed Jun. 16, 2014

    "I found the best way to roll out pie crust and keep it tender and flaky

    is to wipe the counter top with a damp dish cloth then lay a large piece of plastic wrap over that put your pastry dough in the middle cover with another piece of plastic wrap and roll out. take the top layer off and turn the dough over the pan then peel the plastic wrap off. Comes out perfect every time. If you need to you can always patch the crust. Like another person said the less you handle it the better and don't use too much extra flour"

    maggieyoder User ID: 2170439 213204
    Reviewed Jun. 2, 2014

    "This was fabulous! Everyone loved it, and it was definitely put on the "please make it again" list! Very easy to put together."

    vickybilski User ID: 3427924 197214
    Reviewed Apr. 24, 2014

    "jewels2468 as with all pastry crust, the least you handle it the better. Over mixing makes the crust tuff. Plus it sounds like you needed a little more flour on you paper. Practice, and you will be a champ. Good luck"

    veggiemama User ID: 4640590 139116
    Reviewed Jun. 25, 2013

    "This dessert is OUTSTANDING! It was one of the best desserts I've ever made!"

    mbandboys User ID: 2680134 152153
    Reviewed Jun. 10, 2013

    "Every one in my family LOVED these! They all went back for seconds!!"

    jewels2468 User ID: 2727773 152147
    Reviewed May. 24, 2013

    "Help! I couldn't roll this dough out. I tried the method in the recipie and it stuck to the paper and once I pried it from that I just laid it on a lightly floured counter top and after baking it came out real hard. Not flakey and soft. I do like the flavor of the fruit filling. I used strawberries. I love the flavor of strawberry and rhubarb. I would love to try this again, although it took me a lot more time than the recipe calls for. I have never made a pie before so I would like to see if I can do it right. Suggestions would be appreciated."

    donnafinch User ID: 2845945 138114
    Reviewed May. 23, 2013

    "This was absolutely fantastic and the crust super easy! I substituted strawberries for the raspberries. Took to a fellowship and got rave reviews!"

    Eden300 User ID: 1967625 139115
    Reviewed May. 12, 2013

    "I can't even roll out dough for a pie let alone an 18 x 13" piece !"

    ChocolateMudCake User ID: 162783 194648
    Reviewed Jan. 22, 2013

    "Have made this a few times and it is a hit every time. The best part is that it feeds a crowd!!"

    jnatalie User ID: 6897459 123291
    Reviewed Oct. 2, 2012

    "I LOVEEEE this recipe!!!!!!!!!!!!"

    nmblades User ID: 170437 213203
    Reviewed Sep. 20, 2012

    "Very good and simple to make. Has lots of flaky layers."

    jupiter1964 User ID: 3293931 139114
    Reviewed Jul. 25, 2012

    "I got rave reviews from neighbors and friends at work they loved it!!"

    1buswell User ID: 781803 197997
    Reviewed Jul. 24, 2012

    "I am a subscriber. I hauled this recipe with me back to a family reunion to make. Now that I am home, I couldn't find my magazine. Panic. Thanks TOH for having it online! I have also used other fruit with the rhubarb and flipped the ratio of 5 cups rhubarb and 3 of the raspberries with success. Love family recipes. Thanks for sharing yours."

    geec User ID: 6685817 213202
    Reviewed Jul. 5, 2012

    "Loved this bar. I used strawberries instead of raspberries."

    toolbarsco User ID: 6725667 188146
    Reviewed Jun. 6, 2012

    "This recipe is so easy and absolutely deslicious. I've taken the bars to a couple of events and everyone wants the recipe. This is a winner!!"

    kbmst2 User ID: 6554143 116704
    Reviewed Jun. 1, 2012

    "The bars were quite simple to make and tasted delectable!"

    adelle cerruti User ID: 826591 152146
    Reviewed May. 29, 2012

    "Delicious! I used 3 cups of raspberries and two cups of strawberries, plus the rhubarb called for. I used a sl heaping !/3 cup of cornstarch.. For the crust I used the 3/4 cup milk, then add only Tbs. at a time of milk until it forms a ball. I rolled it on a floured piece of parchment a little bigger than a jelly-roll pan. You can then roll the parchment including the crust and unroll it into the pan . Do the same with the top crust. Everyone loved it!"

    daburgers User ID: 3891926 197995
    Reviewed May. 29, 2012

    "Made it exactly as written, was easy and delicious. It will become one of my "Signature Desserts""

    sub-teacher User ID: 6011180 197994
    Reviewed May. 29, 2012

    "I am involved in a potluck twice a month, so this type of recipe is right up my alley! It is easy and quick to make, serves easily, and is great! The first time I served it to company, I didn't think they would ever stop eating it! I have made it in triple berry and loved it. Spectacular crust, too!"

    bakinglynn User ID: 4225827 213201
    Reviewed May. 26, 2012

    "This is FABULOUS!!!! I used Pillbury pie crusts rolled 2 together for bottom then 2 for the top. Works great!!"

    andrea hoke User ID: 2120956 139113
    Reviewed May. 26, 2012

    "Fabulous!! I substitued strawberries for the raspberries since I had fresh strawberries in the garden; it worked out wonderfully. I'm definitely going to make it again this summer when the red raspberries are in season! I loved the rich buttery crust and the glazing. Yum, yum, yum!"

    loowho88 User ID: 6705925 138113
    Reviewed May. 23, 2012

    "simply awesome!"

    subeh User ID: 5714124 197373
    Reviewed May. 18, 2012

    "This went over sensationally at Poker club. I shared the recipe with Mom who has made 3 times in the past 3 weeks. It's great!"

    sassyboots0 User ID: 6461826 126773
    Reviewed May. 16, 2012

    "This is Really, Really Good!!!!!"

    jjandag User ID: 1415746 188144
    Reviewed May. 11, 2012

    "WONDERFUL! I used half whole wheat flour and half white flour and it worked out very well. I completely forgot to put the icing on, and no one missed it. You can still taste the tartness of the rhubarb. I was a little short on raspberries so I used strawberries as well. I'm making this again for the third time now - it is a huge hit!"

    GramaConnie User ID: 3560466 138112
    Reviewed May. 8, 2012

    "Great combination of flavors & pretty too."

    Nikol42 User ID: 4295947 198930
    Reviewed Apr. 20, 2012

    "I made this for Easter and it received RAVE reviews! In fact, the reason I am on the TOH site today is to send the recipe to three different people who requested it! :) I would highly recommend these bars! Thanks so much!"

    Fargirl User ID: 6375134 152139
    Reviewed Apr. 18, 2012

    "My co-workers loved this slab pie!"

    justmeinny User ID: 6448274 116702
    Reviewed Apr. 18, 2012

    "Made by following recipe exactly and it is fabulous!"

    margar7611 User ID: 5255800 123271
    Reviewed Mar. 24, 2012

    "I made this today, but used strawberries on place of the rhubarb only because I didnt have any rhubarb. It is amazing and I'll make it again. Next time I want to try the rhubarb for the tang..."

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