01 -
Add celery, carrots, onion and garlic to a food processor and pulse until finely minced. If you don't have a food processor, mince all vegetables by hand.
02 -
Melt butter with olive oil in a large Dutch oven or soup pot over medium heat. Increase heat to medium-high, add minced vegetables and sauté for 4 minutes until softened.
03 -
Sprinkle flour over vegetables and cook for 1 minute, stirring constantly to prevent burning.
04 -
Gradually whisk in chicken broth followed by tomatoes, basil, oregano, salt, parsley, black pepper, red pepper flakes (if using), and bay leaf. Bring mixture to a boil, then reduce heat and simmer for 15 minutes or until carrots are tender.
05 -
Whisk in Parmesan cheese until melted. Stir in milk, half and half, or cream and gently simmer for an additional 15-20 minutes on low heat, stirring occasionally. Add additional broth or cream to reach desired consistency. Remove bay leaf and season with salt and pepper to taste.
06 -
For a smoother, creamier texture, puree the soup using an immersion blender directly in the pot. Alternatively, work in batches to transfer soup to a blender, being careful to allow steam to escape to prevent pressure buildup. Blend until smooth.
07 -
Ladle bisque into bowls and garnish with additional freshly grated Parmesan cheese if desired.