Preheat oven to 350°F. Melt 2 Tbsp. of the margarine; place in medium bowl. Add 1-1/2 cups of the cereal and the milk; stir. Let stand 1 min. Add egg and 3/4 cup sugar; mix well. Stir in flour, baking powder and cinnamon until well blended. Spread batter into 9×5-inch loaf pan sprayed with cooking spray.
Melt remaining 2 Tbsp. margarine; place in small bowl. Add remaining 1/2 cup cereal and 1 Tbsp. sugar; stir until well blended. Sprinkle over batter. Gently press cereal mixture into batter.
Bake 50 min. or until toothpick inserted in center comes out clean. Cool in pan 10 min; remove to wire rack. Cool completely. Cut into 16 slices to serve.