Preheat the oven to 400°F (200°C) and line a baking sheet with parchment paper.

Wash and cut cauliflower into florets, then toss with olive oil, salt, and pepper in a bowl.

Arrange the cauliflower florets on the baking sheet.

Wrap garlic cloves in aluminum foil with olive oil and place on the baking sheet.

Roast vegetables for 25-30 minutes until cauliflower is golden brown and tender.

Sauté chopped onion in olive oil in a large pot until translucent, about 5 minutes.

Add the roasted cauliflower and garlic to the pot, along with vegetable broth and coconut milk.

Bring the mixture to a simmer for 5 minutes.

Blend the soup until smooth using an immersion blender.

Adjust seasoning with salt and pepper, and serve topped with olive oil or garnished with herbs.