Apple Slab Pie

Makes one, 5 1/2 by 17-inch slab pie 2 lb Golden Delicious apples, peeled and cut into 1/4-inch slices 2 teaspoons fresh lemon juice 1 cup granulated sugar 3 tablespoon all-purpose flour 1 teaspoon vanilla extract 1 teaspoon ground cinnamon 1/8 teaspoon freshly grated nutmeg Egg wash, as needed Sanding or granulated sugar,…