Preheat your oven to 180 degrees Celsius.
Peel the onions using a sharp knife, wash them thoroughly and roughly chop them.
Melt 30 grams butter in a large sauce pan over low heat.
Add the coarsely chopped onion to the hot butter and sauté it on low heat for a couple of minutes, or until soft and translucent, but not coloured.
Add finely chopped sage leaves to the onion and cook for a few more minutes, stirring continuously.
Remove the onion from the heat and stir in a small quantity of coarsely chopped parsley.
Also add coarse, fresh white breadcrumbs and the herby meat sausage.
If you are using zest of lemon, grate it into the sauce pan and mix all the ingredients well to combine.
Add a beaten egg spoon by spoon to the mixture, squeezing it with your fingers until it binds together.
Season your stuffing generously with salt and pepper and mix well.
Use butter to grease your baking dish and transfer the stuffing to it.
Set the stuffing in the dish by pressing it down with a spoon.
Bake it in the oven preheated at 180 degrees Celsius for 30 to 35 minutes or until the top is crisp and golden brown.