It may be more of a winter weather technique, but braising has its place in summer cooking too —namely in these fantastic beer-braised lamb tacos. (Incidentally, if you have leftover meat, it makes a great base for a ragù to serve over pasta.)
Combine the rub ingredients (salt, pepper, chile powder, cumin, coriander, cinnamon) together in a bowl and mix well. Rub all over the lamb shanks so that they are completely covered with the spice mixture.
Place a large pot over high heat, drizzle with a little vegetable oil, and add in the lamb shanks. Sear the shanks for about 2-3 minutes on each side. Reduce heat to low and once the pot is no longer scorching pour in the beer, apple cider vinegar, and tomato paste (if you add in the liquid when the pot is too hot it will result in a very smoky apartment). Make sure that the liquid covers the shanks almost entirely then cover the pot and let it simmer for 3-4 hours. (If you want, you can refrigerate the meat in the braising liquid overnight.)
Remove from heat and once the meat has cooled slightly, enough for you to handle it, use a fork to pull the meat from the bone. To serve, add some of the shredded lamb to a corn tortilla, top with a few slices of avocado, a couple pieces of sliced red onion, and a squeeze of lime juice.