CREAM CHEESE BATTER: Preheat oven to 350'F. In small mixer bowl, beat cream cheese and 1/2 cup sugar until smooth. Beat in 1 egg and vanilla extract; set aside. CHOCOLATE BATTER: In heavy-gauge, medium saucepan over low heat, melt butter and Nestle unsweetened chocolate bars, stirring until smooth. Stir in 1 3/4 cups sugar. Blend in 3 eggs. Stir in flour. Spread Chocolate Batter into greased 13x9" baking pan. Smooth Cream Cheese Batter over top. Swirl metal spatula through batters to marbleize. Bake 30-35 minutes until edges begin to pull away from side of pan. Cool completely; cut into 2" bars. Makes about 2 dozen brownies.