Combine and bake at 350º, 25 - 35 minutes.
Sprinkle with marshmallows and return to oven for 2 minutes - frost immediately.
Prepare frosting -
In a saucepan combine butter, chocolate, cream cheese and milk. Place over low heat to melt. Stir in confectioners sugar and vanilla.
As soon as marshmallows melt - pour frosting over bars and swirl together. Cool.
Preheat oven - 350º
Grease and flour 13x9x2 inch pans
Combine bar ingredients.
In large saucepan over low heat - melt butter and one square chocolate.
Stir in sugar, flour, baking powder, eggs, vanilla. Add nuts. Spread in ban.
Combine filling ingredients in small bowl. Combine the ounces cream cheese with sugar. Add butter, flour, eggs, nuts. Beat until fluffy. Spoon over bar mixture. Sprinkle with chocolate pieces.