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Key Lime Blondie Bars

Here’s my tropical take on a beloved treat. These key lime bars combine the taste of the classic pie with a blondie batter and cream cheese frosting. You can make a thicker crust if desired. —Kristin LaBoon, Austin, Texas
  • Total Time
    Prep: 35 min. + chilling Bake: 25 min. + cooling
  • Makes
    16 servings


  • 1-1/3 cups graham cracker crumbs, divided
  • 1/3 cup plus 2 tablespoons melted butter, divided
  • 3 tablespoons plus 1/4 cup packed brown sugar, divided
  • 2/3 cup butter, softened
  • 1 cup plus 1 tablespoon sugar, divided
  • 2 large eggs, room temperature
  • 1 large egg white, room temperature
  • 3 tablespoons Key lime juice
  • 4-1/2 teaspoons grated Key lime zest
  • 1 cup all-purpose flour
  • 1/2 teaspoon plus 1/8 teaspoon salt, divided
  • 1 teaspoon vanilla extract
  • 1/8 teaspoon ground cinnamon
  • 1/4 cup butter, softened
  • 1/4 cup cream cheese, softened
  • 4 cups confectioners' sugar
  • 2 tablespoons 2% milk
  • 1 teaspoon vanilla extract
  • Key lime slices, optional


  • Preheat oven to 350°. Line a 9-in. square baking pan with parchment, letting ends extend up sides. Combine 1 cup cracker crumbs, 1/3 cup melted butter and 3 tablespoons brown sugar; press onto bottom of prepared pan. Bake 10 minutes. Cool on a wire rack.
  • For blondie layer: In a large bowl, cream softened butter and 1 cup sugar until light and fluffy. Beat in eggs, egg white, lime juice and zest. In a small bowl, mix flour and 1/2 teaspoon salt; gradually add to creamed mixture, mixing well.
  • Spread over crust. Bake until a toothpick inserted in center comes out clean, 25-30 minutes (do not overbake). Cool completely in pan on a wire rack.
  • For streusel, combine the remaining 1/3 cup cracker crumbs, 2 tablespoons melted butter, 1/4 cup brown sugar, 1 tablespoon sugar and 1/8 teaspoon salt, along with the vanilla and cinnamon, until crumbly. Reserve 1/2 cup for topping.
  • In a large bowl, combine all frosting ingredients; beat until smooth. Stir in remaining 1/2 cup streusel. Spread over bars. Sprinkle with reserved topping. Refrigerate at least 4 hours before cutting. Lifting with the parchment, remove from pan. Cut into bars. Store in an airtight container in the refrigerator. If desired, garnish with sliced Key limes.
Nutrition Facts
1 blondie: 422 calories, 19g fat (11g saturated fat), 69mg cholesterol, 283mg sodium, 62g carbohydrate (51g sugars, 1g fiber), 3g protein.

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  • Mindy
    May 27, 2020

    Four cups of powdered sugar...I had my reservations when I read this but always like to make a new recipe just like it is suggested but next time I will cut the Powdered Sugar in half . It was so wet that my husband would not eat it. We cut the frosting off except for a sliver on top so we could eat one. Threw the rest out. Way too sweet!

  • carol
    May 21, 2020

    like lemon bars, but better!

  • Carol
    May 18, 2020

    Absolutely the most refreshing dessert so far.