In a large Dutch oven or heavy-bottom pot, heat olive oil and butter over medium heat until butter melts and begins to foam. Add diced onion, carrot, and celery. Cook, stirring occasionally, until vegetables are softened and translucent, about 6–8 minutes.

Add garlic and flour

Stir in the 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 create a light roux.

Deglaze and simmer

Slowly whisk in the chicken stock and water, scraping any browned bits from the bottom. Add dried thyme, bay leaf, salt, and pepper. Bring to a gentle boil, then reduce heat to maintain a simmer.

Proteins & Vegetables

Add potatoes and chicken

Add the halved baby potatoes to the simmering broth and cook 10 minutes. Then add the diced chicken pieces (or sliced mushrooms for vegetarian). Continue simmering until potatoes are tender and chicken is cooked through, about 8–10 more minutes (internal temperature for chicken should reach 165°F / 74°C).

Add quick-cooking vegetables

Stir in the frozen peas and chopped spinach. Simmer 2–3 minutes until peas are heated and spinach has wilted. Taste and adjust seasoning with additional salt and pepper if needed.

Finishing & Garnish

Finish with cream and herbs

Reduce heat to low and stir in the heavy cream, fresh parsley, and lemon juice. Warm gently for 1–2 minutes—do not boil after adding cream to prevent curdling. If using, stir in grated Parmesan until melted and incorporated.

Remove and discard the bay leaf. Ladle soup into bowls and garnish with an extra sprinkle of chopped parsley and a grind of black pepper. Serve hot with crusty bread if desired.