Prepare the Crust

Begin by whisking the flour, sugar, and salt in a large bowl. Using a pastry cutter or your fingers, cut in the cold butter until the mixture resembles coarse crumbs. In a separate small bowl, beat the eggs with 5 tablespoons of cold water, then gradually add this to the flour mixture, stirring until the dough begins to come together. Add additional cold water if needed, one teaspoon at a time. Divide the dough into two equal portions, wrap each in plastic wrap, and refrigerate for at least 30 minutes to allow the gluten to relax and the butter to firm up.

Preheat Oven & Prep Pan

Set your oven to 375°F (190°C). While it's heating, prepare a 9×13-inch baking pan by greasing it thoroughly to prevent sticking. This ensures easy removal of the apple slices once baked.

Prepare the Apple Filling

In a spacious bowl, combine the sliced apples, granulated sugar, brown sugar, flour, cinnamon, nutmeg, and lemon juice. Toss everything together until the apples are evenly coated with the sugar-spice mixture. The flour will help thicken the apple juices as they bake, preventing a soggy bottom crust.

Assemble the Slices

Take one portion of dough from the refrigerator and roll it out into a rectangle shape that will fit your baking pan. Carefully transfer this dough to the prepared pan, pressing it into the bottom and up the sides. Spread the apple mixture evenly over this bottom crust, then drizzle the melted butter over the apples. Roll out the second portion of dough and place it over the apples, sealing the edges by pinching them together. Cut several small slits in the top crust to allow steam to escape during baking.

Bake

Place the pan in the preheated oven and bake for 40-45 minutes, or until the crust turns a beautiful golden brown and the apples are tender when pierced with a knife. If you notice the edges browning too quickly, cover them with aluminum foil to prevent burning while allowing the center to continue cooking.

Make the Glaze

While the apple slices are cooling, prepare the glaze by whisking together powdered sugar, milk, and vanilla extract until smooth and pourable. If the glaze seems too thick, add more milk one teaspoon at a time until you reach your desired consistency.

Glaze & Serve

Once the apple slices have cooled slightly but are still warm, drizzle the glaze evenly over the top. Allow the glaze to set for approximately 10 minutes before cutting the dessert into squares and serving. This brief setting time helps the glaze adhere properly to the pastry.