BROWNIE CRUST:

3 oz. unsweetened chocolate, chopped
1/4 c. (1/2 stick) unsalted butter
1/2 c. flour
1/8 tsp. baking powder
2 lg. eggs
1 c. firmly packed brown sugar
1 1/2 tsp. vanilla
1/2 oz. semi-sweet chocolate, chopped

FILLING:

12 oz. cream cheese
1 c. brown sugar, firmly packed
3 lg. eggs
1/2 c. sour cream
1 1/2 c. creamy peanut butter

TOPPING:

3/4 c. sour cream
2 tsp. sugar

CRUST: Preheat oven to 350 degrees. Spray 9" springform pan with butter flavored Pam. Melt unsweetened chocolate, butter in top of double boiler or microwave. Cool. Blend flour and baking powder in bowl. In mixer, beat eggs and sugar until fluffy (4 minutes), scrape sides and heat in melted chocolate, vanilla and chopped chocolate. Add dry ingredients until just blended. Spread 1 cup brownie batter over bottom of pan. Bake 17 to 19 minutes until firm. Cool in freezer for 15 minutes.

FILLING: Blend cream cheese and sugar in processor. Add eggs and sour cream. Process on and off until smooth. Add peanut butter with on and off turns until smooth. Using a small knife, spread remaining batter around sides of pan, sealing to baked crust. Pour filling. It won't be as high as brownie batter. Bake 30 minutes until center is set and sides have fallen to form 1" ring around filling.

TOPPING: Blend and spread to 3/4" of edge. Bake 1 minute more. While hot, set on a rack and with small sharp knife go around edge of top only to loosen. Cool. Refrigerate overnight. Remove sides and decorate with peanut butter piped through pastry bag; drizzle semi-sweet chocolate. Chocolate as desired.