Preheat oven to 350F°. Line a baking sheet with a silicone baking mat or parchment paper.
Peel and chop apples. Add to a medium saucepan with cinnamon, brown sugar, water and optional boiled cider. Cook over medium heat until bubbling. When apples are soft, carefully mash with a potato masher until only small pea size chunks remain. Transfer apple mixture to a clean bowl, set aside.
Roll out dough. Cut an even number of rectangles into equal sizes, to create bottoms and tops.
Transfer half of the rectangles to your prepared baking sheet. Add 2 tbsp apple filling to eat rectangle, spread to within 1/4-1/2" from edge of dough. Top off with another piece of dough, pressing down firmly to form the edge. Crimp edges with a fork.
Bake for 20-30 minutes or until lightly golden. Cool on a wire rack.
To prepare the icing; in a small bowl whisk together powdered sugar, milk and caramel extract. Drizzle over cooled pop-tarts. Immediately add sprinkles.
Store in an airtight container for up to several days.