Preheat oven to 400°F.
Let the pastry sheet thaw to room temperature.
Slice and peel apples to 1/4-inch thickness.
Mix apples, sugars, lemon juice, vanilla, salt, cinnamon, and nutmeg. Refrigerate the mixture.
Roll out the pastry with a bit of flour, score edges, and poke holes in the center.
Microwave apricot preserves for 30 seconds, spread on pastry, then add apples on top.
Add cubed butter on top of apples.
Brush pastry edges with egg wash, then bake for 30 minutes. Brush more apricot preserves on top after baking.