How to Make It
Pat the chuck roast dry with paper towels, then rub all over with the ground nutmeg. Sprinkle both sides generously with kosher salt and black pepper.
Warm a Dutch oven on medium-low heat, then add the bacon. Sauté, lowering the heat as needed, until crispy and the fat has rendered, about 8 minutes. With a slotted spoon, remove the bacon; there should be about 1 tablespoon of liquid fat left in the Dutch oven (if there’s less, add a tablespoon of lard or coconut oil). Adjust the heat to medium-high and allow to come to temperature, about 1 minute.
Preheat the oven to 300 degrees. Gently blot any accumulated liquid from the chuck roast with a paper towel, then add the roast to the Dutch oven. Brown on both sides until a deep brown crust forms, about 3 minutes per side, then remove the roast and set aside. Reduce heat to medium and add the diced onion, sautéing until translucent, about 3 minutes. Stir in the tomato paste and sauté until fragrant, about 1 minute. Add the vinegar and wine and deglaze. Return the bacon to the pot, then add the roast, thyme, half of the parsley and the bay leaves. Pour enough stock to cover 3/4 of the roast, then bring to a simmer.
Cover the Dutch oven and put it in the oven. Braise until almost tender, about 2 hours. Add the carrots and celery root and cook until tender, another 30 to 45 minutes.
Gently remove the roast and set aside to rest, covering loosely with tinfoil. Strain the liquid and reserve the bacon and vegetables; set aside. Return the liquid to the Dutch oven and simmer on medium-high heat until reduced by half, about 6 minutes. As it reduces, slice the roast and arrange on a platter with the vegetables. Chop the remaining two sprigs of parsley and thinly slice the lemon zest, then combine. Pour the reduced liquid over the roast and vegetables, then garnish with parsley and lemon zest.