To give the vegetables their moment to shine, other than salt and pepper, I just add a little cumin to this roasted sweet potato cauliflower soup.
1–1/2 pounds sweet potatoes, peeled and diced
1 head orange cauliflower (about 1 pound), trimmed and broken into floret
2 tablespoons olive oil
1 teaspoon cumin
1 teaspoon kosher salt plus more for serving
1/4 teaspoon black pepper plus more for serving
1 small white onion, roughly chopped
4–5 cups water (you can also use veggie or chicken stock)
Chopped fresh parsley for serving
Preheat the oven to 375 degrees F. Line 2 sheet pans with parchment paper.
Toss the sweet potatoes and cauliflower with 1 tablespoon olive oil, cumin, salt and pepper. Spread into a single layer on the prepared sheet pans. Roast until the vegetables start to brown at the edges and the sweet potatoes are tender, about 30 minutes.
Heat the remaining olive oil in a large saucepan over medium heat. Add the onions and sauté for 5-7 minutes until they soften. Add sweet potatoes and cauliflower, reserving 1 cup veggies for garnish and 4 cups water. Simmer for 10 minutes.
Carefully transfer the soup in batches to a blender to puree. Add more water to reach desired consistency, as needed. Return the soup to the saucepan to reheat before serving. Divide into bowls and top with sweet potatoes, cauliflower, parsley, salt and pepper.