Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.
Add the egg yolk, vanilla extract, and lemon zest to the mixture, and mix until well combined.
In a separate bowl, whisk together the all-purpose flour, baking powder, and salt. Gradually add the dry ingredients to the butter mixture, mixing until just combined.
Shape the dough into small balls, about 1 inch in diameter, and place them on the prepared baking sheet, spacing them about 2 inches apart.
Using your thumb or the back of a spoon, create a small indentation in the center of each cookie.
Spoon about 1/2 teaspoon of raspberry preserves into each indentation.
Bake in the preheated oven for 12-15 minutes, or until the edges are lightly golden.
Remove from the oven and allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.
Once cooled, garnish with fresh raspberries and a sprinkle of lemon zest on top.
Notes
Allow cookies to cool completely before garnishing.