The ingredients:
Base:
1/2 cup butter or margarine
1 oz. unsweetened chocolate cut up (I use 1/2 cup semisweet chocolate chips)
1 cup flour
1 cup sugar
1 tsp. baking powder
1 tsp. vanilla
2 eggs
Filling:
1/4 cup butter, softened
1- 8 oz. cream cheese softened (divided)
1/2 cup sugar
2 Tbs. flour
1/2 tsp. vanilla
1 egg
1/4 cup chopped nuts
1 cup chocolate chips
2 cups miniature marshmallows
Frosting:
1/4 cup butter
1/4 cup milk
1 oz. unsweetened chocolate, cut-up ( use 1/2 cup chocolate chips)
Reserved cream cheese
3 cups powdered sugar
1 tsp. vanilla
Heat oven to 350°. Grease and flour 9x13 pan. Melt 1/2 cup butter and 1 oz. chocolate over low heat in microwave,
stirring until smooth.
Stir in remaining base ingredients and spread in pan.
In small bowl combine 6 oz. cream cheese, butter, sugar, flour, vanilla, and egg. Beat until smooth and fluffy. Stir in nuts.
Spread over chocolate mixture 
and sprinkle evenly with chocolate chips.
Bake at 350° for 25 to 35 minutes or until toothpick comes out clean. Remove from oven and immediately sprinkle with marshmallows. Return to oven and bake an additional 2 minutes.
Meanwhile, combine 1/4 cup butter, milk, chocolate and 2 oz. cream cheese and microwave on low heat, stirring until well blended. Add powdered sugar and vanilla; mix until smooth,
immediately pour frosting over marshmallows. Refrigerate 1 hour or until firm. 
Cut into 48 bars. Store in refrigerator. (They're not as messy as you might expect seeing as they contain a layer of melted marshmallows. In fact I'd say they're no messier than any other frosted brownie...and they're tasty enough it would be worth the sticky fingers anyway!) Enjoy!
