The lavender, thyme and rosemary that grow wild throughout the countryside often find their way into southern French cooking.
Heat oil in small skillet, add onion, garlic and peppers, and saute until vegetables are tender. Stir in olives, teaspoon of thyme, the fennel, parsley and bread crumbs. Season to taste with salt and pepper.
Preheat oven to 350 degrees.
Trim as much fat as possible from lamb and spread herb-and-bread-crumb mixture over inside of meat. Roll meat into neat cylinder and tie at inch intervals with butcher string. Also make one tie length of roast so it will hold its shape. (You may also prepare herb mixture in advance and give it to butcher to spread on meat before it is tied for you).
Place lamb in pan and roast until internal temperature of 120 degrees is registered on meat thermometer inserted in middle, or about 20 minutes a pound for total roasting time of 1 hour 10 minutes. Lamb will be medium-rare; increase or decrease cooking time according to individual taste.
Remove lamb from oven and set on carving board or platter to rest for 10 minutes.
Drain fat from roasting pan. Add wine, stock and tomatoes to pan and cook over medium heat, scraping particles from bottom of pan, until sauce is slightly reduced. Season to taste with salt and pepper and add remaining 1/2 teaspoon of thyme.
Carve roast and arrange slices on warmed serving platter and cover to keep warm. Pour any juices from carving board into sauce. Reheat sauce to simmering and, over low heat, add soft butter, whisking it in bit by bit, until sauce is somewhat thickened, glossy and very smooth. Do not allow sauce to come to a boil. Pour a little sauce over sliced meat and serve rest alongside.