Candy-Corn Sugar Cookies

4 tablespoons unsalted butter, very soft 1/2 cup sugar 1 large egg yolk 1/4 teaspoon vanilla extract 1/4 teaspoon baking powder 1/4 teaspoon salt 3/4 cup all-purpose flour, (spooned and leveled) About 36 candy corns

Preheat oven to 350 degrees. Place butter and sugar in a medium bowl; beat with a wooden spoon until combined. Beat in egg yolk, vanilla, baking powder, and salt. Add flour, and mix until a dough forms. Scoop out level teaspoons of dough, and roll into balls (chill dough briefly if it becomes too soft to handle). Place balls on baking sheets, 2 inches apart.

Bake, rotating sheets halfway through, until edges are firm and cookies are dry to the touch (do not let cookies color), 10 to 12 minutes. Remove from oven; gently press a candy corn into center of each cookie (surface of cookies may crack slightly). Cool on sheets 1 minute; transfer to a rack to cool completely.