1. Preheat the oven to 350°F (175°C) and line baking sheets with parchment paper.

2. Beat the softened butter and granulated sugar until light and creamy.

3. Add the eggs one at a time, mixing well after each addition, then add the vanilla extract.

4. In a separate bowl, whisk together the flour, baking powder, and salt.

5. Gradually add the dry ingredients to the wet mixture and mix until a soft dough forms.

6. Scoop small portions of dough and roll them into balls. Place them on the prepared baking sheets, leaving space between them.

7. Bake for approximately 12 to 15 minutes, or until the cookies are set and lightly golden underneath.

8. Allow the cookies to cool on the baking sheets for several minutes, then transfer them to a wire rack to cool completely.

9. Beat the mascarpone and powdered sugar until smooth.

10. Fold the peach preserves into the mascarpone mixture until evenly combined.

11. Combine the milk, granulated sugar, vanilla extract, and peach liqueur in a shallow bowl.

12. Make a small indentation on the flat side of each cooled cookie.

13. Fill one cookie half with the mascarpone-peach filling and gently sandwich it with another cookie.

14. Quickly dip each assembled cookie into the peach coating.

15. Roll the coated cookies in granulated sugar and place them on a tray to set.

16. Decorate with small mint leaves or another edible green garnish if desired.

17. Refrigerate the assembled cookies until ready to serve.