Grease a 13"x 9" pan and preheat oven to 325 degrees.
In a large bowl cream together:
1 cup butter (softened)
3 oz. cream cheese (softened)
2 cups sugar
Gradually beat in:
1 tsp. vanilla
In a separate bowl, sift together:
1 cup flour
3/4 cup unsweetened cocoa powder
1/4 tsp. baking powder
1/2 tsp. salt
Gradually add the dry ingredient to the butter mixture until well blended.
Stir in 3/4 cups chocolate chips. Spread batter into pan and sprinkle the top with 3/4 cup chopped walnuts or pecans.
Bake for 35 to 40 minutes( use the shorter time if you like them fudgy).