Preheat your oven to 425°F (220°C). Cut the large head of cauliflower into florets and toss them in a mixing bowl with olive oil, salt, and pepper. Spread the cauliflower in a single layer on a baking sheet. Roast for 25–30 minutes, stirring halfway, until the florets are golden and tender.

In a large pot, heat a splash of olive oil over medium heat. Add the chopped onion and sauté for about 5 minutes until it becomes soft and translucent. Then, introduce the minced garlic and cook for an additional 1–2 minutes, stirring frequently until it becomes fragrant.

Once the cauliflower is perfectly roasted, add it to the pot along with the vegetable broth. Stir well to combine the ingredients and bring the mixture to a gentle simmer. Let it cook for about 10 minutes.

Using an immersion blender, carefully blend the soup in the pot until it reaches a silky-smooth consistency. If you don’t have an immersion blender, let it cool slightly and transfer the soup in batches to a countertop blender. Stir in heavy cream or coconut milk.

Taste and adjust seasoning with salt and pepper as needed. Gently heat the soup through without bringing it to a boil. Serve hot, garnished with fresh chives or parsley.