Step 1

Sift flour, baking powder, and salt together in a medium bowl.

Step 2

Beat butter in a mixing bowl using an electric mixer until creamy, about 1 minute. Add sugar and beat until blended. Add egg yolks one at a time, followed by blueberries, lemon zest, and vanilla extract. Scrape down the sides of the bowl and beat 1 minute more. Reduce the speed of the mixer to low and add flour mixture, mixing just until a smooth dough forms.

Step 3

Divide dough in 1/2 and shape into logs 1 1/2 inches in diameter and 10 inches long. Wrap logs in plastic wrap and refrigerate until firm, about 2 hours or up to 3 days. Dough can also be frozen at this point and thawed when ready to bake.

Step 4

Preheat the oven to 350 degrees F (175 degrees C). Place an oven rack in the center position.

Step 5

Unwrap 1 dough log and slice into 1/4-inch thick rounds. Place rounds 1-inch apart on an ungreased cookie sheet.

Step 6

Bake in the preheated oven until edges start to turn golden, 9 to 11 minutes. Remove from the oven and transfer to a wire rack to cool completely, 15 to 30 minutes. Dust with confectioners' sugar when cool. Repeat baking process with remaining cookie dough.