Preheat the oven to 180°C.
Coat lamb shanks with flour in a large bag.
Heat 15ml of oil in a frying pan and sear lamb until browned.
Sauté onions in 15ml of oil in a lidded casserole dish until soft.
Add berries, zests, bay leaves, and parsley to the onions.
Place lamb, potatoes, and carrots into the casserole dish.
Deglaze the frying pan with a little stock and add to the casserole.
Pour in remaining stock, orange juice, salt, and pepper and bring to a boil.
Cover and cook in the oven for 60 minutes.
Remove the lid and cook for another 30 minutes.
Remove the lamb, parsley sprigs, and bay leaves from the dish.
Stir in the sour cream and fresh chopped parsley leaves.
Return the lamb to the sauce and serve with gnocchi.