1/2 c. butter
2/3 c. packed brown sugar
2 c. quick cooking rolled oats
1/2 c. chopped nuts or flaked coconut (optional)
1 tsp. vanilla

TOPPING:

1/2 c. chocolate chips
1/4 c. peanut butter

Microwave butter in 1 1/2 or 2 quart mixing bowl at high 45-60 seconds, or until melted. Blend in sugar. Stir in remaining ingredients. Spread in greased 8 x 8 inch baking dish.

Place dish on inverted saucer in microwave oven. Microwave at high 3-6 minutes or until bubbly all over, rotating 1/4 turn after 2 minutes, then every minute. Cool 2 minutes; sprinkle with chocolate chips and drop small spoonfuls of peanut butter here and there. When soft, spread to frost, leaving marbled effect. Cut into strips with sharp knife when frosting is partially firm.