This recipe was inspired by my mother's traditional recipe that she makes for the holidays every year. My personal addition is the horseradish which gives it rich dimension and a piquant finish.
Technique tip: If you don't have a fat separator, pour the liquid into a bowl and freeze it until the fat solidifies, then skim off and discard the fat.
Swap option: Swap in your favorite other roots vegetables like sweet potatoes, turnips or rutabaga.
Preheat the oven to 350°F with the rack in the middle.2.
Season the brisket all over with 1 tablespoon salt and 2 teaspoons pepper.3.
In a large roasting pan set over 2 burners, heat 3 tablespoons of the oil until hot but not smoking. Add the brisket and cook over medium-high heat, turning, until browned all over, 5 to 7 minutes per side. Transfer brisket to a rimmed baking sheet, fat side up.4.
Pour off all but 2 tablespoons of fat from the pan. Add the onions and half of the garlic, and cook over medium heat until softened, about 3 minutes. Add the carrots, parsnips and celery; season with 1/4 teaspoon each salt and pepper. Continue cooking until the vegetables are browned, about 6 minutes. Using a slotted spoon, transfer the vegetables to a plate; set aside.5.
Add the wine to the pan. Bring to a boil over high heat and cook, scraping up browned bits from the bottom of the pot, for 1 minute.6.
Return the brisket to the pan, fat-side up. Add the broth and bay leaves and bring to a simmer over medium-high heat. Cover the pan tightly with foil, sealing the edges; transfer to the oven and cook for 2 hours.7.
Remove the pan from the oven, then carefully loosen and remove the foil. Scatter the reserved vegetables and the potatoes around the brisket. Reseal the pan tightly with the foil, then return it to the oven. Cook until the brisket is very tender, about 1 hour more.8.
Meanwhile, in a small bowl, stir together the kosher for Passover mustard, 1/4 cup of the horseradish and the remaining garlic.9.
Remove the pan from the oven. Carefully loosen and remove the foil. Spread the horseradish mixture over the top of the brisket, then return to the oven and braise, uncovered, until the top is browned, about 20 minutes.10.
Transfer the brisket to a carving board and loosely cover with foil to keep warm. Remove and discard the bay leaves. Using a slotted spoon, transfer vegetables to a serving platter and loosely cover with foil to keep warm.11.
Pour the juices from the pan into a fat separator and let stand until the fat rises to the surface. Pour the cooking liquid into a small saucepan; discard the fat. (If you don't have a fat separator, pour the liquid into a bowl and freeze it until the fat solidifies, then skim off and discard the fat.)12.
Whisk the remaining 1/4 cup horseradish into the cooking liquid, then season to taste with salt and pepper. Thinly slice the brisket against the grain, then transfer to the platter with vegetables. Gently warm the broth over low heat, then spoon a little over the brisket. Pass the remaining broth at the table.
Note: This recipe can be made-ahead through to when the brisket is roasted and the top is browned. It can then be cooled in the liquid and refrigerated, covered, for up to 3 days (keep the vegetables in a separate container, cover and refrigerated). To serve, skim the fat from the surface of the broth. Slice the brisket while it's cold, then arrange it with the vegetables in the broth in a roasting pan or baking dish; cover the pan tightly with foil, sealing the edges. Heat in a 350°F oven, until the vegetables and meat are warmed through, about 30 minutes. Then season the broth as directed above.