Place first 4 ingredients in blender and blend at high speed until onion is pureed. Add next 4 ingredients and blend again. Add cream, 1/3 at a time, and blend until very smooth. Pour into 1-quart mold and chill overnight. To unmold, dip bottom and sides of mold into warm water and invert onto a serving plate. Decorate mousse with parsley. appet 54