PREHEAT oven to 300°F. Microwave margarine and sugar in large microwaveable bowl on HIGH 30 sec. or until margarine is completely melted. Stir in ginger. Add cereal; toss lightly. Spread into single layer in greased 15x10x1-inch baking pan.
BAKE 15 min. Stir in peanuts. Bake an additional 10 min. Cool completely.
ADD cranberries; toss lightly.