Preheat the oven to 350 degrees F. Spray two baking sheets with butter spray.
Add the butter, confectioners' sugar, baking powder, egg yolks, whiskey and vanilla to a large bowl. Mix until thoroughly combined, then add the flour and almonds. Mix together until a dough forms. Pinch off small pieces of the dough and roll them into 1-inch balls. Shape the balls into half-moons and place them 1/2-inch apart on the prepared baking sheets.
Bake for 20 to 25 minutes, or until the cookies are just slightly golden brown. Transfer the cookies to a cooling rack and let cool completely. Roll each cookie in confectioners' sugar and place in cupcake liners.