2 lb flat-cut beef brisket
1/2 tsp kosher salt
1 tsp fresh black pepper, divided
4 cups unsweetened apple cider
1 large onion, peeled and thinly sliced
6 cloves garlic, peeled but left whole
10 sprigs fresh thyme, or 2 Tbsp dried thyme leaf
1 Tbsp cornstarch or arrowroot
Preheat oven to 325°F.
Allow the brisket to come to room temperature (30-60 minutes out of the refrigerator). Season both sides with salt and 1/2 teaspoon of the pepper.
In a high-sided nonstick roasting pan just large enough to hold the meat, brown the meat on all sides over medium-high heat.
When the meat is brown, add one cup of the cider to the pan. It will boil instantly. Let it boil for 30 seconds, then add the onion, garlic and thyme. Cook for another minute, and add the remaining three cups of cider and another 1/2 teaspoon of black pepper.
Cover the pan tightly with a double layer of aluminum foil, and place in the oven. Cook for 4-1/2 hours at 325F. The meat should be fork tender.
Remove the meat to a serving dish or casserole, and cover it lightly with a piece of the aluminum foil from the roasting pan. Place the roasting pan on the stove top over high heat. While the cider is coming to a boil, mix the cornstarch or arrowroot with 2 tablespoons of water, and set aside.
Allow the cider in the pan to boil for 2 minutes. Stir in the cornstarch mixture, and whisk to make sure there are no lumps. The sauce should thicken slightly, but not become gloppy.
With a slotted spoon, remove the onion, garlic and thyme stems from the sauce. Spoon the remaining sauce over the brisket, or serve some in a gravy boat on the table.