Melt the chocolate in the top pan of a double boiler over simmering water.
Remove the top pan from the heat, stir in the sugar and coffee.
Add one yolk at a time stirring until smooth.
Place the top pan over boiling water, cook and stir for 3-4 minutes or until the mixture is thick.
Pour the chocolate mousse into a bowl, chill for 6 -8 minutes.
Fold in 3 cups of the whipped topping
Spoon into dishes, top with whipped topping.
