Let eggs, milk, and butter stand till room temperature. Cream butter, gradually add sugar, beating well. Add eggs, one at a time, beating well after each addition. Combine flour, baking powder, and salt, add to creamed mixture alternately with milk, beginning and ending with flour mixture. Stir in vanilla. Pour batter into 2 greased and floured 9-inch round cake pans or 13x9 inch cake pan. Bake at 350 degrees for 25 minutes or until wooden pick inserted in center comes out clean. Cool in pans 10 minutes; remove layers from pans and cool completely before frosting.