1. In a 2- to 3-quart pan over low heat, stir butter and chocolate until melted and smooth. Remove from heat and stir in vanilla and 2 cups sugar. Transfer to a bowl. Add 4 eggs, one at a time, beating well after each addition. Stir in flour and baking powder until well blended.
2. In another bowl, mix fromage blanc, remaining 1/4 cup sugar, and remaining egg until well blended.
3. Spread half the chocolate mixture evenly in a buttered and floured 9-inch square baking pan. Pour cheese mixture evenly over chocolate. Drop 1/4-cup portions of remaining chocolate mixture on top, partially, but not completely, covering cheese mixture.
4. Bake brownies in a 325° oven until a wooden skewer inserted in the center comes out with moist crumbs attached, 45 to 50 minutes. Let cool in pan on a rack for at least 20 minutes, then cut into 9 squares.
Note: Nutritional analysis is per brownie.