Heat your oven: To 350°F (175°C).

Prepare your brisket: Place your total measured amount of salt in a small bowl. Trim your brisket, if necessary, so that only a thin layer of fat remains — about ⅛- to ¼-inch thick. Season it generously on top with salt from the bowl and many grinds of black pepper.

Brown your brisket: Heat a large Dutch oven over high heat with 1 to 2 tablespoons of oil until very hot. Place the whole brisket (if it fits) or the first half of your brisket (if you need to divide it) seasoned side-down into the hot pan then season the second side (now facing up) generously with more salt from the bowl and pepper. Cook until crusty and well-browned on both sides, about 5 to 7 minutes per side, repeating with the second half of brisket if you needed to divide it. Transfer to a plate to rest.

While the brisket browns, prepare your onions: Halve and peel each onion, and slice a generous ¼-inch thick.

Cook the onions: Add the onions to your empty pot, season with salt from the bowl and pepper, and cook, stirring frequently, until the onions have softened and developed a rich brown color, 10 to 15 minutes. Add the garlic and cook for another minute.

Prepare the braise: Remove the pot from the heat. If you need to transfer the onions and garlic to an ovensafe casserole dish, do so now. Place the browned brisket on the onions and pour any juices that accumulated on the plate over it, plus 1 ½ cups of water. Spread the tomato paste over the top of the brisket. Sprinkle the brisket with additional black pepper and any salt you have left over in your dish. Scatter the carrots in the pan. Cover the pot and transfer to the oven.

Braise your brisket, choosing your next directions based on when you plan to serve it: 1st schedule: Braise your brisket to serve today: Let the brisket cook, untouched, for 1 ½ hours then remove from the oven. Carefully transfer the brisket to a cutting board. Using a very sharp knife, thinly slice the brisket across the grain into approximately ⅛-inch to ¼-inch thick slices. Return the slices to the pot, leaning them slightly so that you can see a bit of the top edge of each slice. If the liquid looks low, add another ½ cup of water at this time. Replace the lid on the pan and return it to the oven for an additional 1 ½ to 2 ½ hours. The brisket is done when you can easily pull a slice apart with a fork.

2nd schedule: Braise your brisket to serve tomorrow or the next day: Let the brisket cook, untouched, for 3 hours then remove from the oven. If the liquid looks low, add another ½ cup water at this time. The brisket is done when you can easily pull a slice apart with a fork. If it’s not done yet, return it to the oven for another 30 to 60 minutes.

Chill brisket overnight, or for two nights: Transfer brisket, covered, to the fridge.

About 1 hour before you plan to serve the brisket: Heat oven to 350°F (175°C). Remove the lid from the pot and use a spoon to remove any solidified fat from the top of and around the meat. Carefully transfer the brisket to a cutting board. Using a very sharp knife, thinly slice the brisket across the grain into approximately ⅛-inch to ¼-inch thick slices. Return the slices to the pot, leaning them slightly so that you can see a bit of the top edge of each slice. Place lid back on pot and warm in oven for 35 to 45 minutes, until slices are hot throughout and the liquid is bubbling.

To serve: Serve the sliced brisket, spooning onions and sauce from the pan over each plate.