Preheat oven to 400°F (200°C). Wrap the garlic bulb in foil and roast for 30-35 minutes until golden.

While garlic roasts, chop cauliflower into florets and rinse under cold water.

In a large pot over medium heat, add olive oil and sauté the diced onion until translucent (about 5 minutes).

Squeeze the roasted garlic into the pot, then add cauliflower florets and vegetable broth. Bring to a boil, then simmer for 15-20 minutes until tender.

Blend the mixture until smooth using an immersion blender or regular blender.

Stir in heavy cream and cheddar cheese until melted. Season with salt and pepper to taste.