Creating Brown Sugar Pop Tart Cookies can be simple if you follow these straightforward steps:

1. Preheat the Oven: Begin by preheating your oven to 350°F (175°C). Line a baking sheet with parchment paper.

2. Mix Dry Ingredients: In a bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

3. Cream Butter and Sugars: In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy.

4. Add Egg and Vanilla: Beat in the egg and vanilla extract until fully incorporated.

5. Combine Dry and Wet Ingredients: Gradually add the dry ingredients to the wet mixture, mixing until just combined.

6. Chill the Dough: Cover the dough with plastic wrap and chill in the refrigerator for about 15 minutes. This step helps the cookies hold their shape during baking.

7. Shape the Cookies: Roll the chilled dough into balls, about 1 inch in diameter. Use your fingers to flatten each ball slightly.

8. Add Filling: Place a small spoonful of brown sugar filling in the center of half of the flattened dough pieces. Top with another piece of dough and seal the edges.

9. Bake: Place the filled cookies on the prepared baking sheet. Bake in the preheated oven for 12-15 minutes or until the edges are lightly golden.

10. Cool: Remove from the oven and let the cookies cool on the baking sheet for about 10 minutes before transferring them to a wire rack to cool completely.

11. Prepare the Frosting: In a small bowl, whisk together powdered sugar, milk, and vanilla extract until smooth. Drizzle over the cooled cookies.

12. Serve and Enjoy: Your Brown Sugar Pop Tart Cookies are now ready to be enjoyed!