Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.

Place the cauliflower florets on the baking sheet, drizzle with olive oil, and season with salt and pepper.

Peel away the outer layers of the garlic head, cut off ¼ inch from the top, drizzle with olive oil, wrap in foil, and place on the baking sheet.

Roast the vegetables for 30-35 minutes, flipping cauliflower halfway through.

Heat 1 tablespoon of olive oil in a large pot over medium heat. Add the diced onion and sauté until translucent.

Blend the roasted vegetables with broth and seasoning in a blender until smooth.

Return the blended soup to the pot. Squeeze roasted garlic into the soup and stir.

Simmer and gradually stir in the shredded cheddar until melted.

Ladle soup into bowls, garnish with green onion and extra cheese, and serve with sourdough.