Simmer water and sugar (without mixing, and preferably in heavy-bottom saucepan) until a drop of the syrup forms a soft ball in cold water (15-20 min, or until it reaches 235°F). If the ball breaks when you press on it, add 1tsp water to the syrup and try again. Beat eggs until fluffy. While still beating, add very thin stream of boiling syrup until fully incorporated. Continue beating until mixture is room temperature (about 10 minutes). Add butter. If the cream curdles, beat in 1/4 cup melted chocolate chips or place bowl over steaming water for a few seconds and mix again. Add coffee Extract. Optionally, separate frosting into two batches (one for inside and one for outside of cake). Beat another 1/2 cup melted chocolate chips into one of the two batches (or both if you did not separate into two batches).