BASE:

1/2 c. butter
1 oz. (1 square) unsweetened chocolate, chopped
1 c. Pillsbury's Best All Purpose or Unbleached Flour
1 c. sugar
1 tsp. baking powder
1 tsp. vanilla
2 eggs
3/4 c. chopped nuts

FILLING:

8 oz. pkg. cream cheese, softened, reserving 2 oz. for frosting
1/4 c. butter, softened
1/2 c. sugar
2 tbsp. flour
1/2 tsp. vanilla
1 egg
1/4 c. chopped nuts
6 oz. pkg. (1 c.) semi-sweet chocolate chips

FROSTING:

2 c. miniature marshmallows
1/4 c. butter
1/4 c. milk
1 oz. (1 square) unsweetened chocolate, chopped
Reserved 2 oz. cream cheese
3 c. powdered sugar, sifted
1 tsp. vanilla

Heat oven to 350 degrees. Grease and flour 13"x9" pan. In large saucepan over low heat, melt 1/2 cup butter and 1 ounce unsweetened chocolate, stirring constantly until smooth. Lightly spoon flour into measuring cup; level off. Add 1 cup flour and remaining base ingredients; mix well. Spread into prepared pan.

In small bowl, combine all filling ingredients except 1/4 cup nuts and chocolate chips. Beat 1 minute at medium speed until smooth and fluffy; stir in nuts. Spread over chocolate mixture; sprinkle evenly with chocolate chips. Bake at 350 degrees for 25 to 35 minutes or until toothpick inserted in center comes out clean.

Immediately sprinkle marshmallows over top. Return to oven and bake an additional 2 minutes. In large saucepan over low heat, combine 1/4 cup butter, milk, 1 ounce unsweetened chocolate and reserved 2 ounces cream cheese; stir until well blended. Remove from heat; stir in powdered sugar and 1 teaspoon vanilla until smooth. Immediately pour frosting over marshmallows and lightly swirl with knife to marble. Refrigerate until firm; cut into bars.