Heat oven to 425. Place oil in 10-inch ovenproof skillet; heat in oven until oil is hot, about 10 t0 12 minutes. Meanwhile, in small bowl combine flour, baking powder. salt and eggs; beat at medium speed until well blended. Gradually stir in milk and margarine. Pour batter into hot skillet. Bake at 425 for 15 minutes. Reduce oven temperature to 375. Bake an additional 10 to 12 minutes or until puffed and golden brown. (A well will form in center and edges will puff up.) In a small saucepan, combine cornstarch and pineapple. Cook over medium-low heat until slightly thickened, stirring occasionally. Fold in coconut and banana slices. Remove pancake from oven; spoon filling into center. Serve immediately..(Pancake will collapse as it cools.) Also works well with apple slices and cinnamon....