I've made these for years. They're killer. I always cut these in BITE SIZE pieces. Put these out late in the evening at your next party. They will always disappear. Great for tailgating, school events, the holidays. The best browine recipe ever!
Preheat oven to 325 degrees. Melt chocolate and butter in small, heavy saucepan, stirring constantly. Remove from heat.
Stir sugar and flour together in large mixing bowl. Add chocolate mixture, eggs, and liqueur, stirring well to combine. Stir in chocolate pieces and nuts.
Spread in buttered 13X9" baking pan. Bake for 35 minutes (NO LONGER, brownies will not look done). Cool 1 hour on wire rack, then cut into bite size pieces (be sure to cut into pieces before chilling or they will be very difficult to cut). Chill overnight before serving.