Tie the celery hearts and cook them in half the butter, salt, and pepper for a good hour in a casserole. Add a little water if necessary during the cooking. On a plate mix the cumin, saffron, salt, and pepper. Roll the monkfish tail in the spices. Preheat the oven to 425F. Sprinkle shallots on the bottom of an ovenproof dish and place the fish on top. Dot with butter, add the white wine, salt and pepper and bake for 30 minutes. When the monkfish is cooked, it is easily detached from the spine. Remove it from the oven dish and keep warm. Reduce the juices to 1/2 cup. Add the crÅme fraöche, season and taste, boil for a few minutes and eventually add the cumin and saffron. Place the monkfish on a serving platter with the celery hearts and the sauce in a sauceboat.
