Preheat oven to 325F. In large bowl, stir cocoa, sugar and flour together, Add shortening and beat till mixture is creamy and smooth. Beat in eggs and instant coffee. Batter will be very stiff, turn into greased 8" square pan. Smooth top so batter is in even layer to cover pan completely. Bake at 325F for 20 minutes or till top is shiny. Test with toothpick, centre should be firm and fudgy. Do not overbake. Cool on wire rack. Icing: Melt butter in pan over medium heat, add coffee. Boil for 2 minutes, stirring frequently. Remove from heat and blend in milk and icing sugar. Beat till icing is smooth. Let icing cool till it is thick enough to spread. Frost brownies. Meanwhile melt 2 squares semisweet chocolate (in microwave or on top of double boiler). Immediately pour melted chocolate into ziploc baggie and seal. Snip corner from bag and squeeze out over frosted brownies in crisscross pattern. With a blunt knife, swirl chocolate and icing together to create marbled effect. Cut into bars when icing has set.