In a large mixing bowl with an electric mixer, cream margarine and sugar until well-blended. Add eggs; mix well.
Combine baking powder and crumbs; add to sugar mixture. Slowly add milk, coconut, nuts and pineapple. Batter will look curdled.
Pour batter into a greased and floured 13x9x2-inch baking pan. Bake in a preheated 375° F oven for 40 to 50 minutes or until done. Cool slightly in pan before cutting into squares. Serve with whipped cream, if desired.Servings: 10