Creating these delectable Brown Sugar Pop Tart Cookies is a straightforward process. Follow these steps for sweet success:

1. Preheat the Oven: Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
2. Mix Dry Ingredients: In a large bowl, whisk together the flour, brown sugar, baking powder, baking soda, and salt until well combined.
3. Cream Butter and Sugar: In another bowl, cream together the softened butter and brown sugar using an electric mixer until light and fluffy (about 2-3 minutes).
4. Add Egg and Vanilla: Beat in the egg and vanilla extract to the creamed mixture until fully incorporated.
5. Combine Ingredients: Gradually add the dry mixture to the wet mixture, mixing until a dough forms. If the dough is too crumbly, add milk one tablespoon at a time until the right consistency is achieved.
6. Shape Dough: Divide the dough in half, wrap in plastic wrap, and chill in the refrigerator for about 30 minutes for easier handling.
7. Roll Out the Dough: Once chilled, roll out one portion of the dough on a floured surface to about ¼-inch thick.
8. Cut Out Shapes: Use a cookie cutter or knife to cut the dough into rectangular pieces (about 3 x 4 inches).
9. Fill with Jam: Place a small spoonful of your chosen filling in the center of half of the cut-out shapes, leaving space at the edges.
10. Top with Second Piece: Place another rolled-out cookie on top of each filled piece and press down the edges with a fork to seal them.
11. Bake: Transfer the cookies to the baking sheet and bake for 15-20 minutes, or until the edges are lightly golden.
12. Cool the Cookies: Remove from the oven and allow the cookies to cool on a wire rack for at least 20 minutes.
13. Make the Icing: In a small bowl, mix the powdered sugar and milk until smooth, then drizzle over the cooled cookies.
14. Add Sprinkles: If desired, top the icing with colorful sprinkles for an extra touch of fun!

With these steps, you can create beautiful Brown Sugar Pop Tart Cookies that are sure to delight everyone!