Roasted Romanesco Soup

Heat the oven to 425°F/220°C. Trim the base of the cauliflower. Cut the cauliflower into about 1/2-inch-thick slices and place the slices in a single layer on a baking sheet (it’s fine if they’re a bit crumbly). Drizzle and coat the slices with 2 Tbsp (30 ml) of oil and sprinkle with 1/2 tsp of the salt and a few grinds of black pepper. Roast in the oven until cooked through and the edges have browned, about 25 minutes, flipping halfway through cooking. Remove from the oven and set aside.

Heat the remaining 1 Tbsp oil in a large pot or Dutch oven over medium-high heat. When the oil is hot and shimmering, add the diced onion and sauté until translucent, about 3 minutes. Add the garlic and cook until fragrant, 30 seconds to 1 minute. Add the roasted cauliflower, but reserve several small pieces as garnish for each bowl of soup. Add the broth, the remaining 1 tsp salt, and several grinds of pepper. Heat until warmed through.

Remove from the heat and use an immersion blender to puree until completely smooth (or transfer the contents of the pot to a blender if you don’t have the immersion type). Put the soup back on the stove until it is just hot (do not bring to a boil). Remove it from the heat and stir in the buttermilk. Taste and adjust the seasoning. Ladle the soup into bowls and garnish with an extra drizzle of buttermilk, the reserved cauliflower pieces, and lots of chives. Serve immediately.