1/2 cup butter
1 ounce unsweetened chocolate
1 cup granulated sugar
1 cup all-purpose flour
1/2 to 1 cup chopped nuts
1 teaspoon baking powder
1 teaspoon vanilla extract
2 eggs

Preheat oven to 350 degrees F. Grease and flour a 13 x 9-inch pan.

In large saucepan, over low heat, melt 1/2 cup butter and 1 ounce chocolate. Add remaining ingredients. Mix well. Spread in prepared pan.

Filling
8 ounces cream cheese, softened
    (reserve 2 ounces for frosting)
1/2 cup granulated sugar
2 tablespoons flour
1/4 cup butter, softened
1 egg
1/2 teaspoon vanilla extract
1/4 cup chopped nuts
1 (6 ounce) package semisweet chocolate chips

In small bowl, combine the 6 ounces cream cheese with next 5 ingredients. Blend until fluffy and smooth. Stir in nuts and spread over chocolate mixture. Sprinkle with chocolate chips. Bake at 350 degrees F for 25 to 35 minutes or until a wooden pick inserted in center comes out clean.

Frosting
2 cups miniature marshmallows
1/4 cup butter
1 ounce unsweetened chocolate
Remaining 2 ounces cream cheese
1/4 cup milk
1 pound confectioners sugar
1 teaspoon vanilla extract

Sprinkle with marshmallows and bake 2 minutes longer. Over low heat, in large saucepan, melt butter, chocolate, cream cheese and milk. Stir in confectioners' sugar and vanilla extract until smooth. Immediately pour over marshmallows and swirl together. Store in refrigerator.