Preheat your oven to 400°F (200°C). Slice off the top of a whole head of garlic, drizzle it generously with olive oil, and wrap it tightly in aluminum foil. Place it on a baking sheet and roast for 35–40 minutes.

While the garlic is roasting, heat a tablespoon of olive oil in a large pot over medium heat. Add the chopped onion and celery, stirring occasionally for 5–7 minutes until they become soft and translucent.

Once the garlic is roasted, carefully squeeze the cloves into the pot, discarding the papery skins. Add the chopped fresh rosemary and stir for 1–2 minutes, allowing the mixture to become aromatic.

Stir in the drained cannellini beans, low-sodium vegetable broth, bay leaf, salt, and black pepper. Increase the heat to bring the soup to a gentle boil. Once boiling, reduce the heat and let it simmer for 20 minutes.

Remove the bay leaf and use an immersion blender to puree the soup to your desired consistency. For a mix of smooth and chunky, blend only half of it.

Stir in fresh lemon juice to brighten the flavors of the soup. Taste and adjust the seasoning with additional salt and pepper as needed.

Ladle the warm soup into bowls, garnishing with croutons, parsley, or a drizzle of olive oil as preferred.