3 tablespoons extra virgin olive oil
2 large leeks, root and tough dark green tops removed, cleaned and medium-chopped
2 stalks celery, cleaned and medium-chopped
3 cloves garlic, finely chopped
1 large head of cauliflower, cleaned, green stem & leaves removed and cut into 2-inch florets
1 quart vegetable stock (or low-sodium chicken stock if preferred*)
3 cups purified water or more stock (more or less as needed)
1 bay leaf
1 1/2 teaspoons red wine vinegar
about 1 tablespoon fine sea salt, more or less to taste
about 1 teaspoon coarse black pepper, more or less to taste
finely chopped chives for garnish
In a large soup pot or dutch oven, heat the olive oil over medium-high heat. Add the leeks, celery, and a big pinch of salt and sauté until soft, about 5-6 minutes. Add the garlic and stir, and cook another minute until very fragrant, being careful not to burn the garlic. Add the stock, 2 cups water, 2 teaspoons sea salt, 1/2 teaspoon pepper and the bay leaf, then bring to a boil.
Add the cauliflower florets and turn the heat to medium; simmer 30 minutes until the cauliflower is fork tender. Discard the bay leaf.
Puree the soup with a hand blender, or in small batches in a high-speed blender or food processor until very smooth. Add the pureed soup back to the pot and stir in vinegar and 1/2 to 1 cup more stock or purified water (depending on desired texture).