PreparationMake brownie: Preheat oven to 350°F. Butter and flour 8 x 8 x 2-inch metal baking pan. Melt butter in medium saucepan over low heat. Add chocolate; stir until chocolate melts. Remove from heat. Whisk in remaining ingredients. Spread batter in thin layer on bottom of prepared pan. Bake until tester inserted into center comes out with moist crumbs attached, about 10 minutes. Cool. Make filling: Reduce oven temperature to 325°F. Stir cream and coffee poweder in small saucepan over medium-high heat until coffee powder dissolves. Cool. Beat cream cheese and sugar in large bowl until light. Beat in egg and yolk. Add sour cream, flour, vanilla and coffee mixture; beat until smooth. Stir in chocolate chips. Spoon filling evenly over brownie. Bake until filling puffs slightly around edges and the center is set, about 35 minutes. Cool completely on rack. Cover pan with foil and chill overnight. Make topping: Stir sour cream and sugar in small saucepan over low heat until sugar dissolves, about 2 minutes (do not boil). Spread topping evenly over filling. Cool slightly. Cover; chill until topping sets, at least 2 hours. (Can be made 1 day ahead; keep chilled.) Cut dessert into 24 bars. Serve cold.
PreparationMake brownie: Preheat oven to 350°F. Butter and flour 8 x 8 x 2-inch metal baking pan. Melt butter in medium saucepan over low heat. Add chocolate; stir until chocolate melts. Remove from heat. Whisk in remaining ingredients. Spread batter in thin layer on bottom of prepared pan. Bake until tester inserted into center comes out with moist crumbs attached, about 10 minutes. Cool. Make filling: Reduce oven temperature to 325°F. Stir cream and coffee poweder in small saucepan over medium-high heat until coffee powder dissolves. Cool. Beat cream cheese and sugar in large bowl until light. Beat in egg and yolk. Add sour cream, flour, vanilla and coffee mixture; beat until smooth. Stir in chocolate chips. Spoon filling evenly over brownie. Bake until filling puffs slightly around edges and the center is set, about 35 minutes. Cool completely on rack. Cover pan with foil and chill overnight. Make topping: Stir sour cream and sugar in small saucepan over low heat until sugar dissolves, about 2 minutes (do not boil). Spread topping evenly over filling. Cool slightly. Cover; chill until topping sets, at least 2 hours. (Can be made 1 day ahead; keep chilled.) Cut dessert into 24 bars. Serve cold.