Season the 2 pounds of cubed lamb shoulder with salt, pepper and herbs de provence. Add 2 tablespoons of Sriracha and 2 tablespoons olive oil to coat the meat. Marinate overnight.
Sear the meat in large heavy-bottomed fry pan or sauté pan over medium-high heat. Once the lamb has caramelization/browning on all sides, drain the meat over a perforated pan and reserve the drippings. Deglaze the pan(s) with red wine, scraping up the fond.
Set the reduced wine aside.
Heat a heavy-bottomed sauce pan or dutch oven over medium-high heat. Add the lamb and fat drippings back to the pan. Add the sugar and caramelize the meat for 1 minute. Add the all-purpose flour to form a "roux." Reduce the heat and add the chopped garlic, red wine & fond and simmer for 5 minutes. Add the tomatoes and reserved juice and simmer for 5 minutes. Add just enough stock to cover the meat. Bring to a boil and reduce the heat to a simmer. Add a bay leaf and cover with parchment paper. Stir occasionally.
The stew is ready when the lamb is tender; approximately 2 hours. Once the meat is tender, re-season the stew with salt, pepper, fresh chopped thyme and more Sriracha to taste.