Cream butter in a large mixing bowl; gradually add sugar, beating well. Add egg yolks, one at a time, beating well.
Combine flour, baking powder, and salt; add to creamed mixture alternately with milk, beginning and ending with flour mixture. Stir well after each addition. Stir in lemon rind and juice.
Pour batter into a well greased and floured 13- x 9- x 2- inch baking pan. Bake at 350° for 35 minutes or until a wooden pick inserted in center comes out clean. Cool completely in pan on a wire rack.
Spread Lemon Cream Frosting over cake. Garnish with lemon bows.