Deluxe Chocolate Marshmallow Brownies

Seriously, you will need a chain saw to cut these, but it's very well worth it.

3/4 cup butter or margarine
1-1/2 cup sugar
3 eggs
1 tsp. vanilla
1-1/3 cup flour
1/2 tsp. baking powder
1/2 tsp. salt
3 tbs. baking cocoa
1/2 cup chopped nuts, optional
4 cups miniature marshmallows
TOPPING
1-1/3 cups (8 oz) chocolate chips
3 tbs, butter or margarine
1 cup peanut butter
2 cups rice Krispies

In a mixing bowl, cream butter and sugar. Add eggs and vanilla; beat 
until fluffy. Combine flour, baking powder, salt and cocoa; add to 
creamed mixture. Stir in nuts, if desired. Spread in a greased 
jelly roll pan (10x15). Bake at 350 degrees for 15-18 minutes. 
Sprinkle marshmallows evenly over cake; return to oven for 2-3 
minutes. Using a knife dipped in water, spread evenly over cake. 
Cool. For topping, combine chocolate chips, butter and peanut butter 
in a small saucepan. Cook over low heat, stiring constantly, until 
blended and melted. Remove from heat; stir in cereal. Spread over 
bars. Chill.
Yeild--about 3 dozen