Cut greens and onion into fine cubes, then lightly sauté in a small amount of oil in the roaster.
Cut rabbit into portion-sized pieces, clean, dry, season with salt, season with pepper. Sauté heartily in butter and oil in a large frying pan. Place the fried pieces on top of the steamed vegetables.
Then dissolve the gravy in the roasting pan with the clear soup, mix with the basil, mustard, mustard seeds and bay leaf seasoning, bring to the boil briefly and pour over the meat.
Cover the roaster tightly with aluminum foil and steam in a heated oven at 200 °C for 75 minutes.
Next, remove the meat (place in a preheated baking dish with a cover) and strain or mash all the vegetables. Stir the whipped cream into the resulting thick sauce and perhaps season with a little salt, pepper and mustard.