Pour a little clarified butter into a heat-proof casserole over moderate heat. Add the onions into the hot butter and fry until opaque. Add the rice. Wrap the 6 mussels in aluminum foil and place on top of the rice. Cover and let cook for 60 seconds. Pour the white wine over the rice and stir. The mussels will be opening up after 2 minutes. Remove the foil wrapped mussels and set aside. To the rice, add the chicken, ham and the shrimps. Sprinkle with salt and pepper. Place the casserole in a preheated 450 degree oven for 20 minutes. Remove from the oven and moisten with 1/8 cup dry white wine and decorate with mussels. Sprinkle with lemon juice and garnish with chopped parsley.