Apple Slab Pie

A classic American dessert featuring a double slab crust and a filling of mixed apples, baked in a half-sheet pan for 24 generous servings.

Ingredients

• 5 cups All-Purpose Flour (spooned and leveled)
• 2 tablespoons Granulated Sugar
• 2 teaspoons Salt
• 1 cup Unsalted Butter (very cold, cut into small cubes)
• 1 cup Vegetable Shortening (chilled)
• 3/4 to 1 cup Ice Water
• 1 large Egg (beaten with 1 tablespoon of milk for egg wash)
• 2 tablespoons Coarse Sugar (for sprinkling on top)
• 4 to 5 pounds Apples (mix of Granny Smith and Honeycrisp, peeled, cored, and thinly sliced)
• 3 tablespoons Lemon Juice
• 3/4 cup Granulated Sugar
• 3/4 cup Light Brown Sugar (packed)
• 2 teaspoons Ground Cinnamon
• 1/2 teaspoon Ground Nutmeg
• 1/4 teaspoon Ground Allspice
• 1/2 teaspoon Salt
• 1/2 cup All-Purpose Flour (for thickening)
• 3 tablespoons Unsalted Butter (cut into small pieces)
• 1 and 1/2 cups Confectioners’ Sugar
• 2 to 3 tablespoons Milk
• 1 teaspoon Vanilla Extract

Instructions

1. Make the Flaky Pastry Dough: In a large mixing bowl, whisk together the flour, granulated sugar, and salt. Add the chilled, cubed butter and cold vegetable shortening. Using a pastry cutter or your fingers, quickly cut the fats into the flour mixture until it resembles coarse crumbs with pea-sized pieces of butter remaining. Drizzle in 3/4 cup of ice water, stirring gently with a fork just until the dough comes together. If the dough is too dry, add the remaining ice water a tablespoon at a time. Divide the dough evenly into two equal portions. Shape each portion into a flattened rectangle, wrap tightly in plastic wrap, and chill in the refrigerator for at least 45 minutes.
2. Prepare the Apple Filling: Peel, core, and thinly slice your apples. Place the slices into a very large mixing bowl. Toss the apple slices immediately with the fresh lemon juice to prevent oxidation. In a separate bowl, whisk together the granulated sugar, brown sugar, cinnamon, nutmeg, allspice, salt, and all-purpose flour. Pour the dry spice and flour mixture over the apples and toss thoroughly until every slice is evenly coated. Set aside while you roll out the crust.
3. Assemble the Slab Pie: Preheat your oven to 375°F (190°C). Lightly grease your half-sheet baking pan with butter or non-stick baking spray. On a well-floured work surface, roll out the first portion of chilled dough into a large rectangle, roughly 14×19 inches, so it comfortably covers the bottom and sides of your baking sheet. Gently transfer the dough into the prepared baking pan, pressing it smoothly into the corners and up the sides. Evenly spread the prepared apple filling over the bottom crust. Scatter the small pieces of unsalted butter evenly across the top of the apples. Roll out the second portion of dough for the top crust. You can place it as a solid sheet (make sure to cut several slits for steam to vent), or cut it into strips to create a classic woven lattice design. Trim any excess overhang from the edges, fold the bottom crust edges over the top crust, and crimp or press them together securely to seal.
4. Bake to Golden Perfection: Brush the top crust evenly with the prepared egg wash (egg and milk mixture) to ensure a glossy, golden-brown finish. Sprinkle the coarse sugar evenly across the top for a delightful sweet crunch. Bake in the preheated oven at 375°F (190°C) for 35 to 40 minutes. The pie is done when the crust is deeply golden brown and you can see the apple juices bubbling thickly through the vents or lattice. Remove from the oven and transfer the baking sheet to a wire rack. Allow the pie to cool for at least 30 to 45 minutes so the filling can set properly before slicing.
5. Glaze and Serve: While the pie cools, whisk together the confectioners’ sugar, milk, and vanilla extract in a small bowl until smooth. Drizzle the vanilla glaze back and forth over the slightly warm slab pie. Cut into 24 uniform square portions, serve warm or at room temperature, and enjoy!

Notes

Apple Selection: Combining tart apples (like Granny Smith) with sweet, crisp apples (like Honeycrisp or Braeburn) creates a dynamic flavor profile that prevents the pie from tasting overly sweet. Keep Ingredients Cold: For the flakiest crust possible, make sure your butter and water remain as cold as possible throughout the mixing and rolling process. If the dough becomes too warm or sticky, pop it back into the fridge for 15 minutes. Storage: Store leftover slab pie covered tightly in the refrigerator for up to 4 days. Rewarm individual slices in the microwave or oven before serving.