Heat butter in a frying pan; add apples and mix to coat with butter.
Cook for 3-4 minutes; add 1 tbsp. of sugar, 1 tsp cinnamon and nutmeg and continue cooking for 2-3 minutes, until apples are soft, but not mushy.
Transfer apples to a bowl and cool.
Once cooled gently stir in vanilla, sea salt and flour.
Roll dough to 1/8” thickness. Use a small bowl to cut 4” circles. Place a heaping tbsp. of apple mixture on one side of dough. Fold the other side over the apples and seal edges with a fork.
Place on a cookie sheet that has been lined with parchment paper.
Brush dough with egg wash, sprinkle with cinnamon sugar mixture and bake for 18-20 minutes.