BAR:

1/2 c. butter
1 square unsweetened chocolate or 1 env. pre-melted chocolate
1 c. sugar
1 c. flour
1/2 - 1 c. chopped nuts
1 tsp. baking powder
1 tsp. vanilla
2 eggs

FILLING:

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

FROSTING:

2 c. miniature marshmallows
1/4 c. butter
1 square unsweetened chocolate
Remaining 2 oz. cream cheese
1/4 c. milk
3 c. powdered sugar
1 tsp. vanilla

Preheat oven to 350 degrees. Grease and flour 9"x13" pan. In large saucepan, over low heat, melt 1/2 cup butter and 1 ounce chocolate. (Lightly spoon flour into measuring cup; level off.) Add remaining bar ingredients; mix well. Spread in prepared pan.

In small bowl, combine 6 ounces cream cheese with next 5 filling ingredients. Beat 1 minute at medium speed until smooth and fluffy; stir in nuts. Spread over chocolate mixture. Sprinkle with chocolate pieces. Bake 25 to 35 minutes until toothpick inserted in center comes out clean. Remove from oven; sprinkle with marshmallows. Bake 2 minutes longer.

Meanwhile, in large saucepan, over low heat, melt 1/4 cup butter, 1 square chocolate, remaining 2 ounces cream cheese and milk. Stir in powdered sugar and vanilla until smooth. Immediately pour over marshmallows and swirl together. Cool; cut into bars. Store in refrigerator.