A great lemon mousse modeled after the recipe in Professional Baking, the text book used at Le Cordon Bleu.
Top with a raspberry or mandarin orange slice. 
Make a simple syrup by combining in a small sauce pan and bringing to boil and then removing from the heat:
Whisk together and beat until smooth:
Form the base by tempering the egg mixture into the simple syrup by slowly drizzling the syrup into the egg mixture while whisking constantly.