Here is my choc mousse recipe- it's really easy and looks terribly impressive
To serve about 8- 10- you can double or halve this as you need:

500g DARK chocolate
1 tbs butter
1 heaped tbs cocoa
9 eggs- separated
500ml( 2cups) cream
flavouring- I use coffee( 2tsps strong instant in 1 tbs hot water) or you can use 2 tbs of your favourite liquer if u drink

Melt choc , add butter , cocoa, and when slightly cooled, egg yolks, and flavour
Whisk egg whites till stiff - fold in
Whisk cream till stiff- fold in
pour into glass bowl and leave in fridge at least overnight
Decorate with whatever- I use choc curls
and there you have very impressive mousse
Enjoy:-))
TBS= tablespoon= 15 ml
TSP= teaspoon= 5 ml
500g= 1 pound