Easy Chocolate Mousse

0 Separate the yolks from the egg whites.
1 Cut the chocolate bar into small pieces and place it in a pan with two tablespoons of water. Melt the chocolate over low heat while stirring.
2 Once the chocolate has melted, remove from the stove and add the sugar, the egg yolk, Grand Marnier and mix well until a smooth cream is formed.
3 Mix the egg whites until they form hard peaks. Add them one spoonful at a time to the chocolate mixture until they are fully incorporated.
4 Slowly fold in the crème fraiche until all is blended. 
5 Pour into four small glasses or a bowl and refrigerate until ready to serve.