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Triple Berry Slab Pie

  • Author: Julie
  • Prep Time: 1 hour
  • Cook Time: 35 minutes
  • Total Time: 1 hour 35 minutes
  • Yield: 15 squares 1x
  • Category: Dessert
  • Method: Bake
  • Cuisine: American


This Triple Berry Slab Pie has a tart, flavorful filling, and a flakey, delicate crust. You will be so excited to share a piece with someone you love!



For the Pie Crust

  • 1 cup (or one baking stick) shortening, cubed and chilled
  • 1/2 cup butter (I used salted), cubed and chilled
  • 3 3/4 cup all-purpose flour
  • 1/2 teaspoon salt
  • 10 tablespoons ice cold water
  • 7 cups frozen berries (I used blueberries, blackberries, and raspberries)
  • 1/4 cup sugar
  • 2 tablespoons cornstarch
  • 1 tablespoon orange or lemon juice
  • 1 egg plus 1 tablespoon milk
  • dusting of confectioners sugar


  1. In a large bowl, using a pastry cutter, cut butter and shortening into the flour and salt until the largest clumps of flour coated butter and shortening are the pea sized.  Add ice cold water, a tablespoon or two at a time, and mix until a crumbly dough forms.  Knead dough together a few times to bring together and separate into two disks.  Wrap each disk of dough in plastic wrap and chill for at least 3 hours.
  2. When you are ready to assemble the pie, add the frozen berries, sugar, cornstarch and orange or lemon juice to a medium saucepan.  Bring to a gentle simmer over medium heat, stirring occasionally.  Allow the berries to simmer and thicken for 3-4 minutes then remove from heat and allow to cool to room temperature while you form the pie.
  3. Preheat oven to 375 degrees. Remove the dough from the refrigerator and place it between two large pieces of plastic wrap.  Roll from the center, turning the dough as you go, until you have a 13 by 18 inch rectangle.  The dough will be thin.  Remove the top piece of plastic wrap and flip the dough over onto a 10 by 15 inch jelly roll pan.  Remove the second sheet of plastic wrap, and gently press the dough (without stretching it) into the pan.   Roll the overhanging edges of the dough under and press them to the side of the pan.
  4. Pour the filling evenly over the bottom crust.
  5. Roll out the remaining dough into a 10 by 15 inch rectangle.  Using a knife, pizza cutter, or pastry crimper, cut ten strips of dough 1 inch wide by 15 inches long.  It may help to use a ruler for this.  Place one strip of dough in the center of the pan diagonally.  Trim the rest of the pieces to fit about 2 inches apart.  I used 5 strips going in one direction, and then crisscrossed with the five remaining strips.   If your strips of dough get too soft to work with, pop them into the freezer for a few minutes to firm them up.  Don’t be afraid to patch the dough together if they crack or break.
  6. In a small bowl, whisk egg and milk together.  Brush the wash over the top crust and edges.
  7. Bake the pie for 35-40 minutes or until the top is golden brown.  Allow to cool and then dust with powdered sugar and cut into squares.


  • Serving Size: 1 Square Serving
  • Calories: 348
  • Sugar: 8.6g
  • Sodium: 126mg
  • Fat: 21g
  • Saturated Fat: 9.6g
  • Unsaturated Fat: 9.9g
  • Trans Fat: 0.3g
  • Carbohydrates: 37g
  • Fiber: 3.4g
  • Protein: 4.4g
  • Cholesterol: 36mg

Keywords: triple berry slab pie, berry pie, blueberries, blackberries, raspberries, pie