Preheat oven to 325 F Dry brisket and season with salt and pepper on both sides. Heat oil over medium-high in a large roasting pan. Brown the brisket, about 4 minutes per side Add the leeks, carrots and garlic. Add the wine, tomato paste, and thyme and stir. Bring to boil and season with salt and pepper. Cover, remove from stove, and braise in oven for 2 1/2 - 3 hours or until tender. Transfer meat to carving platter and carve against the grain. Place the pan over medium high heat and cook the sauce to reduce (if needed) 3-5 minutes. Adjust seasoning. Put meat on serving platter, pour sauce over meat, garnish with parsley, and serve! If made in advance, remove congealed fat and reheat at 350 F for approx 30 minutes before serving.