In a large heavy-bottomed pot or Dutch oven, warm the olive oil and butter over medium heat until butter is melted and shimmering (about 1–2 minutes).

Add the diced onion, carrots, and celery to the pot and cook, stirring occasionally, until onion is translucent and vegetables begin to soften, about 6–8 minutes.

Aromatics & Flavor

Add the minced garlic and cook for 30–45 seconds until fragrant, stirring to avoid browning.

Stir in the thyme, oregano, bay leaf, salt, and black pepper. Cook together for another 30 seconds to bloom the dried herbs.

Vegetables & Add-ins

Pour in the broth and water, scraping any browned bits from the bottom of the pot with a wooden spoon.

Add the diced potatoes. Bring the mixture to a gentle boil, then reduce heat to a simmer. Simmer uncovered until potatoes are just tender, about 10–12 minutes.

Add the zucchini, corn, peas, and drained tomatoes. Continue to simmer 5–7 minutes until all vegetables are tender but still hold shape.

If using cooked shredded chicken or white beans, add them now to warm through for 3–5 minutes. If using frozen proteins, ensure they reach safe temperature before serving.

Stir in the chopped spinach or kale and simmer 1–2 minutes until wilted.

Finishing & Garnish

Taste the soup and adjust seasoning with additional salt and pepper as needed. Remove and discard the bay leaf.

Stir in the lemon juice and chopped parsley. If using, sprinkle in the grated Parmesan and red pepper flakes; stir until combined.

Ladle the soup into bowls and serve hot. Offer additional Parmesan and lemon wedges at the table.