Heat oven to 350. Grease bottom only of 13x9 inch pan. In large bowl, combine all brownie ingredients. Beat 50 strokes by hand. Spread in greased pan. Bake at 350 for 30 minutes. Remove from oven.
Meanwhile, in small bowl, beat 1/4 cup butter and brown sugar until light and fluffy. Add 1 egg, 2 tsp coffee granules and 1 tsp vanilla; blend well. In medium bowl, combine walnuts and chopped chocolate. Add brown sugar mixture; blend well. Spoon and carefully spread over partially baked brownies. Bake at 350 for an additional 17 to 20 minutes or until lightly brown.
In small saucepan over low heat, melt chocolate chips and 1 tbsp butter, stirring constantly until smooth. Remove from heat. With wire whisk, stir in 1/8 tsp coffee granules and enough milk for desired drizzling consistency. Drizzle over warm brownies. Cool completely. Cut into bars.