Preheat the oven to 350 Degrees
Combine flour, salt and pepper.
Wipe brisket with a damp paper towel then dredge the meat in the seasoned flour.
Heat the oil in a large roasting pan with a cover.
Brown the meat, starting fat side down, on both sides to seal in the juices.
Spread the minced garlic over the top.
Pour the O Champagne vinegar over the meat, letting it drip onto the pan.
Bring to a slow boil, basting the meat until the ingredients are blended.
Cover the pan and place in the oven to braise for 1 hour.
Meanwhile, wash the carrots and the potatoes. Cut the carrots into 1-inch pieces. Leave the smaller potatoes whole and cut the larger potatoes in half or in thirds. Place the potatoes in a bowl and cover with cold water until ready to add to the brisket.
After 1-hour in the oven, remove the brisket and add the carrots, potatoes, brown sugar, DelGrosso Marinara sauce, bay leaves, and dried thyme. Cover and return to the oven for another hour.
Continue to baste occasionally, adding a small amount of boiling water as needed.
Peel and slice the onions into 1/2-inch slices. Set aside.
After the second hour in the oven, remove the brisket and lay the onions in a single layer over the top and sides of the meat and baste.
Cover the pan and return to the oven for about 30-45 minutes or until the onions are tender.
Taste for seasoning and add salt and pepper as needed.
Let meat stand 1/2-hour, then slice across the grain.