I like to sauté vegetables with spices before adding them to water to make soup. Concentrating the sweetness of the vegetables by sautéing them gives so much more flavor—between that step and the spices, you don’t even need to use stock. Stovetop pan roasting is also a way to develop flavor without over- cooking the vegetables. Another trick to creating a flavorful vegetarian stock is adding tomato paste and soy sauce. Both are rich in umami, which lends an almost meaty depth to the soup base. In this master recipe, limon omani (which is dried Persian lime) brings a welcome acidity without discoloring the vegetables the way fresh citrus juice would. It nicely complements the classic French flavors of pepper, sage, bay leaves, and thyme.
Crack and crush the limon omani into smaller pieces by pressing it against a cutting board with your palm, then transfer to a spice grinder along with the bay leaves, sage, thyme, and white peppercorns. Finely grind them together.
For the Soup
Heat a large Dutch oven or other heavy pot over medium-low heat. Add enough oil (about 3 tablespoons) to coat the bottom generously and add the leeks, celery, onions, carrots, cabbage, and celery root. Stir well and add the spice blend. Stir until all the vegetables are evenly coated with the spices, cover, and cook, stirring occasionally, until the onions are translucent around the edges, about 5 minutes.
Reduce the heat to low and add the tomato paste and soy sauce. Stir continuously for 2 minutes and then add 5 cups cold water. Cover the pot and raise the heat to high. When the liquid comes to a boil, reduce the heat to maintain a steady simmer.
Simmer, covered, until the vegetables are almost tender, about 8 minutes. Add the cauliflower and season to taste with salt. Stir, cover, and simmer until all the vegetables are tender, about 15 minutes. Remove from the heat, season to taste with salt, and serve hot.
Recipe Note
Variations & Ideas:
Creamy vegetable soup:
When all the vegetables are blended together, they become luxuriously creamy without any cream. You can garnish this with croutons (toasted nuts or seeds are delicious too) for a little crunch. Follow the vegetable soup recipe above. At the end of step 3, transfer the vegetables to a blender using a slotted spoon. Add just enough of the cooking liquid to barely cover the solids. Blend the soup until very smooth and creamy, working in batches if needed and adding more of the cooking liquid if you prefer a thinner soup. (For an even more refined puree, strain the soup through a fine-mesh sieve.)
