Preheat the oven to 350 degrees. Lightly butter and flour a 9 by 13-inch baking pan and set aside. Blend the flour with salt and coffee and set aside.
In a double boiler, over medium heat, melt the chocolate. When melted, add the butter and melt, over low heat and stir until smooth; let cool to room temperature. While this is cooling, cut the white chocolate into bit sized bits
With an electric mixer beat the eggs and sugar for about 5 minutes or until light, thick and ribbony. When the chocolate has melted, fold it into the eggs along with the vanilla. Gently with a rubber spatula, fold the flour into the batter in a few smooth swift strokes. Do not over mix or the brownies will be heavy. Fold in the white chocolate chunks and transfer the batter into the prepared baking pan. Bake for 20 to 25 minutes or until the top springs back when you press it lightly with your fingertips or when a toothpick when inserted in center of dough comes out clean. Remove from the oven and let set until completely cool. Cut into rectangles and wrap individually in plastic wrap or foil to keep them very fresh.