In a large bowl, cream butter and sugar until light and fluffy. Beat in the eggs, egg whites and extract until well blended. Combine flour and baking powder; gradually add to creamed mixture, beating well after each addition. Stir in pineapple.
Pour into a greased 10-in. fluted tube pan. Bake at 350° for 55-60 minutes. Cool for 10 minutes before removing from pan to a wire rack to cool completely. In a small bowl, combine glaze ingredients. Drizzle over cake.