Sift together flour, baking powder, and salt. Combine egg yolks, milk, and vanilla. Add flour mixture to creamed mixture alternately with egg yolk mixture, beginning and ending with flour mixture; beat on medium speed of electric mixer for 3 minutes.
Spoon batter into greased muffin pans, filling half full. Bake at 375° for 20 minutes or until cupcakes test done. Cool in pans 10 minutes; remove from pans, and cool completely. If desired, spread any frosting over tops of cupcakes.