Oven-braised lamb shanks with sweet potatoes

This is a really straightforward use of lamb shanks, which are a meat I really like. The quantities below are for 1-2, depending on the size of the lamb shank and appetite.

1 1/2 tablespoons olive oil
1 medium/large onion, sliced
2 garlic cloves, chopped
1 bullion cube (chicken)
2 medium sweet potatoes, sliced (peel if you like, I don't)
1 large lamb shank, or 2 small ones (I used 2 shoulder shanks tonight)
1/3 cup white wine
1 bayleaf
1/2 teaspoon dried thyme (fresh is better if you have it, of course)

1. Put oil in casserole dish, making sure it covers the bottom. Put lamb shank(s) in, roll around in oil until they are covered completely.
2. Pre-heat oven to 180 c (350 f), and put lamb in. Let it cook for 10 minutes or so, until lamb starts browning.
3. Remove lamb, and insert onion (and cover dish). Put back in oven until onion starts going clear (about 5-6 minutes for me)
4. Add garlic, thyme, salt, and pepper, and return to oven for 2-3 minutes.
5. Stir everything well, and add lamb and sweet potato slices. Cover about halfway with water, and add wine, bayleaf and crumble the bullion cube into the liquid.
6. Cover the casserole dish, and put in oven for 45 minutes. Turn the lamb shanks over, then cook for about 45 more minutes, when lamb is so tender it falls off the bone.
7. Optionally, If you like your meat a bit crispier, turn the meat over once more, and cook for 10-15 minutes uncovered.

If you feel like it, once you remove the lamb and potatoes, you can strain the liquid, reduce it and add a little flour to make a gravy. I don't normally bother.