Mix the flour, baking powder, salt, and sugar. Beat the egg slightly. Add cereal, milk, and oil to the egg. Stir to combine. Let stand for 2 min. or until the cereal has softened. Stir the pineapple, including the juice, into the mixture. Add flour mixture, stirring only until combined. Spoon the batter evenly into a paper-lined muffin tin and bake at 400F for about 25 min. Serve warm.