In a microwave-safe bowl, melt butter and chocolate; stir until smooth. Cool slightly. In a small bowl, beat the egg, sugar and coffee granules.
Stir in vanilla and chocolate mixture. Combine flour and baking powder; graduall add to the chocolate mixture.
Spread into a 9-inch x 5in, loaf pan coated with cooking spray. Sprinkle with nuts.
Bake at 350° for 20-25 minutes or ntil brownies begin to pull away from sides of pan. Cool on a wire rack.