Take a pot and heat some water. Melt the coffee and chocolate over that pot of hot water. Take the bowl off and put butter into the mixture. Make sure that you beat butter one piece at a time in order to make a batter with a smooth consistency.

Beat sugar and egg yolks together until the mixture thickens. Make sure that the egg mixture is yellow and forms a dissolving ribbon. Put some orange liquor into the mixture and beat it.

Take a pan and pour some water into it. Heat the water on a medium to high heat. Set the bowl containing the mixture over hot water. Make sure that the water is not boiling. It should be warm, but not simmering. Continue beating for about 3 to 4 minutes until the egg-and-orange-liquor mixture is foamy. Take it off when you think the mixture is too hot for you to touch.

Take a pot full of cold water and put the bowl containing egg yolk, sugar and liquor mixture over it and continue beating for another 3 to 4 minutes to the point when it cools down and start forming the ribbons again. The mixture will start having a consistency and uniformity of mayonnaise.

Beat the chocolate and egg yolks together.

Put egg whites in a bowl and beat them together with salt until soft peaks are formed. Once you get to that point, sprinkle sugar over it and beat the mixture until stiff peaks start to form. Take about 1/4 of the egg whites and stir them into the chocolate mixture. Take the rest and fold it in.

I put the mousse in wine glassses, chill at least 2 hours or overnight. Serve with some whipped cream.