- 1/2 cup olive oil
- 2 large Spanish onions, quartered
- 1/2 head celery, roughly chopped
- 1 large leek, split, well washed, and cut into large pieces
- 2 large carrots, peeled and roughly chopped
- 1 (15.5-ounce) can crushed tomatoes
- 1 cup sliced button mushrooms
- 2 pounds Idaho or russet potatoes, quartered
- 5 flat-leaf parsley sprigs
- 2 thyme sprigs
- 2 garlic cloves, smashed
- 1/2 teaspoon fine sea salt
- 1/2 teaspoon black peppercorns
- 2 whole cloves
- Pour the oil into a heavy-bottomed stockpot or lobster pot. Add all the other ingredients and cook, stirring, over medium-low heat until the vegetables have all softened but not colored, about 15 minutes. Pour in 6 quarts water, raise the heat to high, and bring the water to a boil, then lower the heat and let the liquid simmer for 2 hours.
- Carefully strain the stock through a fine-meshed strainer set over a large bowl or pot, pressing down on the solids with a wooden spoon to extract as much liquid and flavor as possible. Let the stock cool, then refrigerate for up to 1 week or freeze in batches to be thawed and used as needed.