Step 1: Roast the Garlic to Perfection
Preheat your oven to 400°F (200°C). Slice about ½-inch off the top of each head of garlic to expose the cloves. Place them on a piece of foil, drizzle with the olive oil, and sprinkle with a pinch of salt. Wrap the foil into a tight packet and roast for 40-45 minutes, until the cloves are deeply golden, soft, and caramelized. Let them cool until safe to handle.

Step 2: Sauté the Aromatic Vegetables
While the garlic roasts, melt the butter in a large Dutch oven or heavy-bottomed pot over medium heat. Add the chopped onion and celery. Cook, stirring occasionally, for 6-8 minutes until softened and translucent but not browned.

Step 3: Squeeze and Incorporate the Roasted Garlic
Once the roasted garlic is cool, squeeze the soft, fragrant pulp from each clove directly into the pot with the onions and celery. It should come out like a paste. Discard the papery skins. Stir for one minute to coat the garlic in the butter and release its aroma.

Step 4: Add Potatoes and Liquids
Add the cubed potatoes, fresh thyme, and bay leaf to the pot. Season with a teaspoon of salt and a few grinds of black pepper. Pour in the chicken broth and water. Bring to a boil, then reduce the heat to low, cover, and simmer for 20-25 minutes, or until the potatoes are very tender.

Step 5: Puree the Soup to Silky Smoothness
Remove and discard the bay leaf. Using a stand blender or an immersion blender, carefully puree the soup until it is completely smooth. If using a stand blender, work in batches and do not fill the blender more than halfway, as the hot liquid can expand and cause burns. For an ultra-silky texture, pass the pureed soup through a fine-mesh strainer back into the pot, pressing with a spatula.

Step 6: Finish with Cream and Cheese
Return the smooth soup to the stove over low heat. Stir in the heavy cream and grated Parmesan cheese. Heat gently until warmed through, but do not allow it to boil. Taste and adjust seasoning with more salt and pepper as needed. For a final touch of brightness, stir in a small squeeze of fresh lemon juice.

Step 7: The Grand Finale – Garnish and Serve
Ladle the hot, creamy soup into warm bowls. Garnish generously with fresh chives, a sprinkle of crispy shallots or croutons for texture, and an optional drizzle of truffle oil. Serve immediately.