Homemade Apple Slab Pie

8 cups peeled, cored, and sliced apples

1 cup white sugar

½ cup brown sugar

1 teaspoon ground cinnamon

¼ teaspoon ground nutmeg

2 tablespoons all-purpose flour (to thicken)

1 teaspoon vanilla extract (optional)

For Topping (Optional):

1 tablespoon butter, cut into small pieces

1 egg, beaten (for egg wash)

1 tablespoon sugar (for sprinkling)

Instructions

Prepare the Crust: