Preheat your oven to 400°F. Slice the tops off the garlic bulbs, drizzle with olive oil, and wrap them in foil. Roast for 30-35 minutes until soft and golden brown.

In a large pot, melt the butter over medium heat. Add the chopped onion and sauté for about 5-7 minutes, stirring frequently, until it's translucent and fragrant.

Peel and dice the potatoes, then add them to the pot along with the broth. Bring to a boil, then reduce to a simmer. Cook for 20-25 minutes, or until the potatoes are tender.

Once the potatoes are tender, squeeze the roasted garlic cloves into the pot. Mix well, allowing the sweet garlic flavor to meld with the potatoes and broth.

Using an immersion blender, blend the soup until it’s smooth and creamy. If you don’t have an immersion blender, carefully transfer batches to a countertop blender.

Return the blended soup to low heat. Stir in the heavy cream, salt, and black pepper. Heat gently for about 5 minutes, ensuring everything is warmed through.