Line baking sheets with parchment paper.

In the bowl of a stand mixer fitted with the paddle attachment, beat butter, confectioners’ sugar, and salt at medium speed until fluffy, 2 to 3 minutes, stopping to scrape bottom and sides of bowl. Beat in egg yolks and vanilla. Add flour and baking powder, beating until combined.

Using a 3-tablespoon spring-loaded scoop, scoop dough (about 55 grams each), and roll into 2-inch balls. Place 3 inches apart on prepared pans. Using a spring-loaded scoop or a small spoon, press down center of each dough ball, creating a 1½-inch indentation, gently pressing together outer edges of dough to seal any large cracks. Freeze until firm, about 20 minutes.

Preheat oven to 350°F (180°C).

Bake until bottoms are golden brown, 16 to 18 minutes. Press down centers again. Let cool on pans for 5 minutes. Remove from pans, and let cool completely on wire racks.

Just before serving, spoon about 1½ tablespoons (45 grams) Lime Filling into center of each cooled cookie. Garnish with lime zest and slices, if desired. Refrigerate in an airtight container for up to 3 days.