In a small bowl, mix coffee and water. Sprinkle with gelatine and let soften 5 minutes. Cook in microwave for about 15 seconds. Stir and repeat the same step, if needed, until gelatine has completely melted and coffee is dissolve. Let rest for 5 minutes.
In a large bowl, mix eagle brand and gelatine mixture. With a spatula, add the cool whip to the cool whip mixture by folding delicately. Pour the mixture in the graham crust and put in the fridge for 45 minutes or until the filling is set. Sprinkle with chocolate if wanted.