In a large heavy-bottomed pot or Dutch oven, heat olive oil and butter over medium heat until butter melts and starts to foam (about 1 minute). Add the diced onion, carrots and celery. Cook, stirring occasionally, until vegetables are softened and the onion is translucent, 6–8 minutes.

add garlic and flour

Add minced garlic and cook 30 seconds until fragrant. Sprinkle the flour over the vegetables and stir constantly for 1–2 minutes to cook the raw flour taste and form a light roux.

deglaze and add liquids

Slowly pour in 1 cup water while stirring to loosen any fond, then add the 6 cups of stock, stirring to fully combine and smooth out any lumps from the roux.

Vegetables & Protein

add potatoes and simmer

Add the diced potatoes to the pot. Increase heat to bring the soup to a gentle boil, then reduce to a simmer. Partially cover and simmer until potatoes are tender, about 12–15 minutes.

add remaining vegetables and protein

Add the diced zucchini, frozen corn and rinsed white beans. If using chicken, add the diced chicken pieces now. Stir to combine. Add the dried thyme, dried oregano and bay leaf. Continue simmering until zucchini is tender and chicken is cooked through (if using), about 6–8 more minutes.

Herbs, Seasoning & Finish

season and finish

Remove the bay leaf. Taste and season with kosher salt and freshly ground black pepper, adjusting to preference. If you want a creamier soup, stir in the heavy cream or half-and-half and warm through (do not boil) for 2–3 minutes.

brighten and garnish

Stir in the chopped fresh parsley and lemon juice to brighten flavors. Keep warm off the heat for 1–2 minutes before serving.

To Serve

Ladle soup into warm bowls. Top each bowl with about 1/2 tablespoon grated Parmesan. Serve with crusty bread or crackers on the side.