Created by Cookiemama on February 12, 2012
Step 1: Grease 9x13 pan.
Step 2: Preheat oven to 350 degrees.
Step 3: In heavy saucepan or microwave, melt butter and chocolate; stir until smooth.
Step 4: Remove from the heat; blend in sugar and vanilla. Add eggs; mix well. Combine the flour, baking powder and salt; add to chocolate mixture. Stir in walnuts, if using.
Step 5: Pour into greased pan.
Step 6: Bake in oven for 25-30 minutes or until top springs back when lightly touched. Cool on wire rack while preparing topping.
Step 7: Combine sugar, milk and butter n a large heavy saucepan; bring to boil over medium heat. Reduce heat; simmer, uncovered, for 5 minutes, stirring constantly.
Step 8: Remove fromo heat. Stir in the chocolate chips, marchmallow creme and vanilla until smooth. Add walnuts, if using.
Step 9: Spread over warm brownies. Freeze for 3 hours or until firm.
Step 10: Cut into 1-inch squares. Store in refrigerator.