In a medium bowl place the eggs and sugar, and beat them together for 3 to 4 minutes, or until eggs are light in color.
Add the melted chocolate and coffee, and stir them in until the mixture is smooth.
In anther medium bowl place the heavy cream and whip it until it is stiff.
Add the vanilla and stir it in.
Gently fold the whipped cream into the chocolate mixture.
Preheat the oven to 35 F.
Pour the mixture into a buttered 9" springform pan.
Place the pan in a baking dish that is half filled with hot water.
Bake the mousse cake in the water bath for 1 hour.
Turn off the heat and let the cake sit in the oven for another 15 minutes.
Remove the cake from the oven and let it cool for 3 minutes.
Sprinkle on some powdered sugar and serve it with vanilla ice cream