"When I was a little girl, my grandmother used to make the best brisket using onion soup to cook it in. My mother made hers differently with tomato sauce...Both were delicious, so I decided one chilly day to make my own hybrid version of both of theirs. What I got was a tender, juicy brisket bursting with flavor, perfect for holiday gatherings or cozy dinners at home."
Slice one onion into large pieces and spread at the bottom of the roasting pan.
Dice one onion and set aside.
Crush the 8 cloves of garlic, and set aside.
In a medium bowl, combine the onion soup and 1.5 cans of water. Add the diced onions and tomato sauce. Stir.
Rub Kosher salt and ground pepper on all sides of the brisket (I usually use about half a handful of salt on each side)
Rub the pressed garlic on all sides of the brisket.
Place brisket in pan, fat side up. Pour the tomato/soup mixture over the brisket and make sure the liquid also gets under the brisket. There will be a lot of liquid--don't worry--it's good!
Cover tightly with lid or foil. Place in the oven and cook half way (about one hour per pound). Check the brisket to make sure there is still enough liquid. I never have to add any, but if you do, add more onion soup and water.
At the half-way mark, flip the brisket. (I usually do this at 2 hours for a 4 pound brisket).
Cook until brisket is tender all around. The center will often take longer, so make sure that the center is as tender as the edges when poking with a fork. 170 on the meat thermometer is a good gauge.