Mix crushed cereal with melted margarine. Set aside. Stir together flour, baking powder, and salt. Set aside. Beat the 1/4 cup margarine, the sugar, and egg until well blended. Add milk alternately with flour mixture, mixing until smooth. Spread batter in greased 9" round cake pan. Top evenly with cranberry sauce. Sprinkle with cereal mixture. Bake at 350~ about 50 mins. Serve warm or cooled.