This soup uses a very simple technique that is time-consuming, to be sure, but requires very little attention and rewards you with loads of rich flavor. Consider this a Sunday-afternoon-on-the-back-of-the-stove kind of dish.

Although I use carrots, celery, celery root, and one of my favorite underutilized vegetables here — parsnips — you can use any variety of root vegetables that you have on hand or that look good at the market. Just be sure to use at least a few different kinds to lend real depth of flavor to the soup. I add the vegetables toward the end of cooking to keep the flavors bright and save them from turning to mush.

Any leftovers will make Monday-night dinner a snap, and the soup even improves if made in advance. Be sure to cool it properly in the fridge and taste for seasoning the next day. You may want to thin it with a little additional water if it’s too thick upon reheating.

Steps

1. Place the oxtail in a stockpot or Dutch oven over high heat and cover with 2 inches of water. Bring to a boil, then decrease the heat to low and simmer for 3 to 4 hours. Check the pot occasionally to skim off any foam and top off the water as necessary to keep the oxtail covered. Cook until the meat easily pulls away from the bone.
2. When the oxtail is ready, remove from the water with tongs and place on a sheet pan to cool. Strain the stock through a fine-mesh sieve or chinois and then skim the fat. You should have about 2 quarts of stock. If not, add water to make 2 quarts. Set aside. When the oxtail is cool enough to handle, remove the meat from the bones and discard the bones.
3. Heat the olive oil in a Dutch oven or stockpot over medium-high heat and add the onion and garlic. Sauté until the vegetables are soft but not colored. Add the farro and stir to coat in the oil. Add the stock and bring to a boil, then decrease the heat to low and simmer until the farro is almost tender, about 20 minutes.
4. When the farro is nearly tender to the bite, add the parsnip, carrot, celery root, celery, and meat. Simmer for about 20 minutes longer, or until the vegetables are tender. If making ahead, remove the soup from the heat at this point to cool, then refrigerate. If serving immediately, add the minced parsley and serve.