Season lamb with salt and pepper. Heat 4 tablespoons oil in heavy-bottomed Dutch oven over medium-high heat. Add lamb and cook until browned, 10–12 minutes, working in batches if necessary. Transfer, using a slotted spoon, to plate.
Add remaining 2 tablespoons oil to fat in pot. Add onion, garlic, rosemary and thyme, cook over medium-high heat until onions are softened, about 5 minutes. Add potatoes and cook another 2 minutes. Add wine and bring to a boil. Cook until liquid is reduced by half, stirring to deglaze the pan, about 5 minutes.
Return lamb to pot, add olives and stock, and bring to a boil. Reduce heat to medium-low and simmer until lamb is tender and potatoes are cooked through, 35–45 minutes.
Serve with crusty French baguettes, or fresh-baked sourdough bread.