1 head cauliflower (about 2 1/4 pounds), cut into florets, or about 6 cups)
2 tablespoons vegetable oil
1 teaspoon salt
1 tablespoon butter
3 onions, sliced 1-inch thick
1/2teaspoon turmeric
1/2teaspoon dried coriander
1/2teaspoon hot paprika or chili powder
1 teaspoon cumin
4 cups water
2 cups chicken or vegetable broth
1 cup yogurt or labnne (optional; adjust to suit tastes)
Preheat oven to 450° F. On a baking sheet, toss cauliflower with vegetable oil and 1 teaspoon salt. Spread out and roast until the florets turn brown, about 25 minutes. Set aside 1/2 cup of the crispiest florets for garnish.
Melt butter in a pot over medium-high heat. Add onions and cook until soft, about 5 minutes. Stir in spices, cauliflower, water, and broth; cover, and bring to a boil. Uncover, lower heat, and simmer 5 minutes.
Using an immersion blender, blend the soup until a desired consistency is reached. Stir in yogurt or labne if using. Season with salt and pepper and serve in bowls, garnishing with the reserved cauliflower florets.
