In a large bowl, mix flour, salt, and sugar.

Cut in the cold butter until the mixture resembles coarse crumbs.

Add ice water, 1 tbsp at a time, mixing until the dough comes together.

Divide into two discs, wrap in plastic, and chill for at least 1 hour.

2️⃣ Make the Apple Filling

In a large bowl, toss apple slices with granulated sugar, brown sugar, cinnamon, nutmeg, lemon juice, and flour. Set aside.

3️⃣ Assemble the Slab Pie

Preheat oven to 375°F (190°C).

Roll out one disc of dough into a rectangle slightly larger than your baking sheet. Transfer to the greased sheet pan.

Spread the apple filling evenly over the dough, leaving a 1-inch border.

Roll out the second dough disc and place over the apples. Trim edges and crimp to seal. Cut small slits in the top for steam to escape.

Brush with beaten egg and sprinkle with coarse sugar, if using.

4️⃣ Bake

Bake for 45–55 minutes, until the crust is golden and apples are tender.

Let cool slightly before slicing.

💡 Tips:

For extra flavor, toss apples with 1 tsp vanilla extract or 2 tbsp bourbon.

Serve warm with whipped cream or vanilla ice cream.