In a skillet, cook 2 medium apples, 2 tbsp butter, 2 tbsp brown sugar, and 1 tsp cinnamon for 5–7 minutes. Add 1 tsp cornstarch if needed and cool.
Roll out 1 package store-bought pie crust cut into rectangles or circles.
Fill half the rectangles with apple mixture, cover with the other half, and crimp edges.
In a small bowl, break the 1 egg, and whisk with a fork.
Brush the tops of the pop-tarts with beaten egg to give them a golden, glossy finish.
Air fry at 350°F for 8–10 minutes until golden brown.
Mix ½ cup powdered sugar and 2 tablespoons milk, drizzle glaze, and enjoy warm.