Preheat your oven to 425°F and position a rack in the center.

Arrange halved tomatoes and unpeeled garlic cloves on a baking sheet with olive oil and salt. Roast for about 25 minutes.

In a large soup pot, warm a splash of olive oil over medium heat and sauté the chopped onion for about 5 minutes.

Add drained cannellini beans, roasted tomatoes, and garlic to the pot, along with 4 cups of vegetable broth. Simmer for 10 minutes.

Remove from heat and use an immersion blender to puree the soup until mostly smooth.

Return the pureed soup to low heat. Stir in fresh thyme, adjust seasoning, and cook for another 5 minutes.

Ladle soup into bowls and garnish with fresh basil and red pepper flakes. Serve with warm crusty bread.