In a large soup pot over medium heat, add the olive oil and butter. When butter is melted and foaming, add the diced onion, carrot and celery. Cook, stirring occasionally, until softened and translucent, about 6–8 minutes.

Add the minced garlic, thyme sprigs and bay leaf and cook 1 minute until fragrant, stirring so garlic doesn't brown.

Deglaze & Add Liquid

Optional: Pour in the white wine and scrape any browned bits from the bottom of the pot. Let the wine reduce by half, about 1–2 minutes.

Add the chicken or vegetable stock and 1 cup of water. Increase heat to bring to a gentle boil.

Main Vegetables & Protein

Stir in the diced potato and tomatoes. Reduce heat to a simmer and cook, uncovered, for 8–10 minutes until potato begins to soften.

Add the diced zucchini and rinsed cannellini beans. Continue to simmer for another 6–8 minutes until all vegetables are tender and beans are heated through.

Remove and discard the thyme sprigs and bay leaf. Stir in the chopped baby spinach and cook 1–2 minutes just until wilted.

Seasoning & Finish

Season the soup with kosher salt, freshly ground black pepper and red pepper flakes if using. Taste and adjust seasoning as needed.

Stir in the lemon juice to brighten the flavors. If you prefer a creamier texture, use an immersion blender to purée 1–2 cups of the soup (or remove 1–2 cups to a blender, purée, then return) and stir to combine.

Ladle soup into bowls, sprinkle each with grated Parmesan and chopped parsley. Serve hot.