Cut out the rabbit. Marinate (including head and offal) overnight with carrots, onion, leek peeled and chopped, herbs, salt and pepper, celery and wine.
For the baeckeoffe, peel and slice leeks and carrots. Peel the new onions, keep them whole with a piece of fane and cut the potatoes into slices about 0.5 cm thick. Drain the pieces of rabbit, make them come back slightly (leaving them blond) in an oil-butter mixture. Reserve the marinade.
Brush the inside of a terracotta casserole with goose fat. Arrange first layer of vegetables and potatoes. Place the rabbit pieces and cover with the remaining vegetables, potatoes and all finely chopped herbs. Be sure to salt, pepper, nutmeg the different ingredients as they are stacked.
Moisten with the marinade all the mixed vegetables, the aromatics of the marinade and the other ingredients. Place the lid on the terrine and seal around the edges with a bead of dough made of flour and a little water. This wrestling operation makes it easier to keep steam in the terrine. Bake in a hot oven at 180 ° / 200 ° (th 6/7) for 2 hours to 2:30.
Place the terrine on the table and serve with a green salad.