Cut the ham and liver into small pieces, add crushed garlic, rosemary, black pepper and salt. Stuff the chicken with the mixture and sew up the opening.
Salt and sprinkle it with lemon juice. Put the chicken in a small greased pan, cover it tightly with aluminum foil. Bake for 2 hours at 302°F (150 °C). Remove the foil and bake for another 10 minutes to redden.
Boil the peeled and coarsely chopped potatoes in a little salted water. Drain them, put the butter in, cover the pot and shake it vigorously.
Put the potatoes in a fireproof pan and put the chicken on top.