Preheat oven to 400 degrees F (200 degrees C). Coat a 23 cm (9-inch) square baking pan with non-stick cooking spray.
Topping: In medium bowl, mix together sugar and flour. Using pastry blender, cut in margarine until mixture resembles coarse crumbs. Stir in cranberries. Set aside.
Cake: In small bowl, mix together flour, sugar, baking powder and salt. Set aside.
In large mixing bowl, mix together cereal and milk.
Let stand for 5 minutes or until cereal is softened.
Add egg and margarine; beat well.
Add flour mixture, stirring only until combined.
Spread batter evenly in prepared pan.
Sprinkle with cranberry topping.
Bake in preheated oven for about 45 minutes or until wooden pick inserted in centre comes out clean.