The saying “grandma knows best” applies to her recipes too. This vintage rhubarb custard pie recipe feels as if it’s straight from Grandma's recipe box, without the streaks of rhubarb juice smudging the directions.

Rhubarb Custard Pie

This rhubarb custard pie recipe is a masterclass in balancing flavor, and you have your grandma’s generation to thank for it. Tart, bitter rhubarb gets baked in a creamy sweet custard sauce, mellowing and melding into a tangy, rich filling. The soft center is encased between two flaky, buttery pie crusts, creating a gorgeous textural contrast that makes every single bite exciting.
The cinnamon-sugar topping is completely optional, but it’s totally worth the extra 30 seconds of effort. We keep things easy with a no-cook custard and premade pie dough, but the simplicity doesn’t take away from the experience of enjoying this vintage custard rhubarb pie recipe that has stood the test of time.
Ingredients for Rhubarb Custard Pie
- Eggs: You’ll need three large eggs to help create the custard.
- Milk: Unlike some other recipes that contain milk, we do not recommend swapping in cream or nondairy milk for the 2% milk. The milk-to-water ratio is accounted for in this rhubarb custard pie recipe so the custard can set up nicely. However, you can use whole milk if desired.
- Sugar: To sweeten the custard and balance out the tart and bitter rhubarb, you’ll need 2 cups granulated sugar.
- Tapioca: Quick-cooking tapioca and tapioca starch are not the same thing, so don’t use the starch as a direct replacement. You can normally find quick-cooking tapioca in the baking aisle.
- Pie crust: We keep this custard rhubarb pie recipe easy by using premade pie crusts. Buy the best premade pie crust from the store so your crusts brown beautifully and have a flaky, buttery texture.
- Rhubarb: Feel free to use fresh or frozen rhubarb here. See our tips section below on thawing rhubarb.
- Butter: Cut the butter into small cubes so you can dot them all over the top of the filling.
- Heavy cream: While optional, heavy cream can be brushed onto the pie crust before baking to promote browning.
- Cinnamon sugar: If you want a little extra flavor with this pie, sprinkle cinnamon sugar on the top as soon as the custard rhubarb pie recipe is pulled out of the oven.
Directions
Step 1: Make the custard mixture
Preheat the oven to 425°F. In a small bowl, lightly beat the eggs, then whisk in the milk. In a separate bowl, whisk together the sugar and quick-cooking tapioca, and whisk it into the egg mixture. Let the custard mixture stand for 15 minutes.
Step 2: Assemble the pie
Meanwhile, on a lightly floured surface, roll out half the dough to 1/8-inch-thick circle. Transfer the pie dough to a 9-inch pie plate. Trim the pie dough so it’s even with the rim.
Add the rhubarb to the crust. Pour the egg mixture evenly over the rhubarb. Dot with the pieces of butter.
Step 3: Top with the second pie crust
Roll the remaining dough to 1/8-inch-thick circle. Place the pie dough over the filling. Trim, seal and flute the pie dough edge. Cut slits in the top. If desired, brush the top crust with heavy cream for extra browning power.
Editor’s Tip: From braids and fluted edges to fun cutouts, there are lots of decorative pie crusts to try out! Or, if you’re up for a challenge, learn how to make a lattice pie crust that looks as though it was weaved by a pro baker.
Step 4: Bake the pie
Bake the pie for 15 minutes. Reduce the oven setting to 350°F, and continue baking the pie until the crust turns lightly brown, 35 to 40 minutes longer. Once the pie is out of the oven, sprinkle it generously with cinnamon sugar if desired.
Editor’s Tip: No matter what pie I’m baking, I always place a baking sheet on the oven rack that’s underneath the pie in case anything bubbles over and out of the pie. It’s much easier to clean a baking sheet than the bottom of an oven!
Step 5: Chill and serve
Let the pie cool on a wire rack at room temperature for one hour. Then, refrigerate the pie for at least three hours before serving so the custard can chill and set and the flavors have a moment to meld together. Cover and refrigerate any leftovers.
Recipe Variations
- Make your own crust: Not a fan of store-bought pie crust? You can totally make your own with a favorite double pie crust recipe instead.
- Add a dash of nutmeg: For a little more flavor, freshly grate 1/4 teaspoon nutmeg into the rhubarb custard pie recipe. Nutmeg pairs especially well with bitter rhubarb and is an amazing secret weapon for custard-based recipes.
How to Store Rhubarb Custard Pie
Cover the custard rhubarb pie recipe with storage wrap and store it in the fridge. It can be kept for up to four days. Keep in mind, though, that the crust will get a bit soggier as the days go on, but it will still taste great!
Can you freeze rhubarb custard pie?
No, we don’t recommend freezing this rhubarb custard pie recipe. Freezing delicate custard pies like this one isn’t the best choice as they can start to weep excess liquid and the crust could become soggy.
Rhubarb Custard Pie Tips
How can you avoid making a runny rhubarb custard pie?
Rhubarb naturally contains a lot of water and is often cooked beforehand or combined with tapioca in baking. In this pie, we accommodate for any extra liquid by using quick-cooking tapioca. The tapioca will absorb most of the liquid, so there shouldn’t be any concerns over a runny custard rhubarb pie recipe.
Should you thaw frozen rhubarb before using it in rhubarb custard pie recipe?
Yes, it’s a best practice to thaw frozen rhubarb before using it. Thaw it in the refrigerator or at room temperature, draining any excess liquid before using it in rhubarb dessert recipes.
Rhubarb Custard Pie
Ingredients
- 3 large eggs
- 3 tablespoons 2% milk
- 2 cups sugar
- 3 tablespoons quick-cooking tapioca
- Dough for double-crust pie
- 4 cups diced fresh or frozen rhubarb
- 2 teaspoons butter
- Half-and-half cream, optional
- Cinnamon-sugar, optional
Directions
- Preheat oven to 425°. In a small bowl, lightly beat eggs; blend in milk. Combine sugar and tapioca; stir into egg mixture. Let stand for 15 minutes.
- Meanwhile, on a lightly floured surface, roll one half of dough to a 1/8-in.-thick circle; transfer to a 9-in. pie plate. Trim even with rim. Add rhubarb to crust. Pour egg mixture over rhubarb. Dot with butter.
- Roll remaining dough to a 1/8-in.-thick circle. Place over filling. Trim, seal and flute edge. Cut slits in top. If desired, brush top crust with cream.
- Bake for 15 minutes. Reduce oven setting to 350°. Bake until lightly brown, 35-40 minutes longer. If desired, sprinkle with cinnamon-sugar. Cool on a wire rack for 1 hour. Refrigerate for at least 3 hours before serving. Refrigerate leftovers.
Nutrition Facts
1 piece: 604 calories, 26g fat (16g saturated fat), 133mg cholesterol, 349mg sodium, 87g carbohydrate (52g sugars, 2g fiber), 7g protein.