Cook the sausage in a large saute pan, breaking it up into small pieces. Add the onions and celery to the pan and cook for about 5 minutes or until softened.Add the cauliflower and cook for about 8 minutes. You want it to brown and caramelize a bit, so don't stir too often. Add the white wine and cook on medium heat until no liquid remains in the bottom of the pan.Add the walnuts and cook for about 2 minutes. Remove from the heat and stir in the parsley and sage. Season with salt and pepper to taste.Try not to eat it all before your guests arrive!