Add turmeric and lamb, browning the lamb on all sides.
Add 2 cups stock, and simmer the lamb on low for about 20-30 minutes.
Add chopped herbs and continue to cook for another 15 to 20 minutes.
Add the sliced rhubarb, gently stir until rhubarb is submerged and then cook (WITHOUT STIRRING) for another 5 to 8 minutes. Stirring will break up the rhubarb, it's very tender at this point.