Preheat your oven to 400°F (200°C). Slice off the tops of the garlic bulbs, drizzle with olive oil, wrap in foil, and roast for 30 minutes until golden and soft.

Heat 2 tablespoons of olive oil in a large pot over medium heat. Add the chopped yellow onions and sauté for 5 to 7 minutes until translucent.

Squeeze the roasted garlic cloves into the pot, pour in the broth, and toss in thyme. Stir and bring to a gentle simmer.

Reduce heat to low and simmer uncovered for 15 to 20 minutes.

Remove thyme sprigs and blend the soup until smooth and creamy using an immersion blender.

Return the soup to low heat, stir in heavy cream, and season with salt and black pepper to taste.

Ladle the soup into warm bowls, garnish with fresh herbs or croutons, and serve immediately with crusty baguette.