01 - Preheat oven to 350°F. Line baking sheets with parchment paper.
02 - In a large bowl, cream together the butter and sugar until light and fluffy.
03 - Beat in the egg and vanilla extract until well combined.
04 - In a separate bowl, whisk together the flour, salt, and baking powder.
05 - Gradually add the dry ingredients to the wet mixture, mixing just until incorporated.
06 - Scoop tablespoon-sized balls of dough and roll them into smooth balls. Roll each in pastel sprinkles or colored sanding sugar for a festive look.
07 - Place balls 2 inches apart on prepared baking sheets.
08 - Bake for 8–10 minutes, until edges are set but centers are still soft.
09 - Remove from oven and immediately press a chocolate blossom kiss into the center of each cookie.
10 - Let cookies cool on the tray for 5 minutes, then transfer to a wire rack to cool completely.