In a medium saucepan over medium heat, warm the butter and olive oil until butter is melted and foaming. Add the diced onion and cook, stirring frequently, until translucent and softened, about 4–6 minutes. Add the minced garlic and cook 30–45 seconds until fragrant.

Make a light roux

Sprinkle the all-purpose flour over the softened onions and garlic. Stir constantly for 1–2 minutes to cook the raw flour taste, creating a thin roux that will slightly thicken the soup.

Add stock

Slowly pour in 4 cups of vegetable or chicken stock while whisking to avoid lumps. Increase heat to bring the mixture to a gentle simmer.

Seasonal Vegetables & Add-ins

Simmer vegetables

Add 1 cup of your chosen seasonal vegetable (diced carrot, squash, potato, mushrooms, or a combination) to the simmering stock. Reduce heat to maintain a gentle simmer and cook until the vegetables are tender, 10–20 minutes depending on the vegetable. Taste for doneness — root vegetables take longer, delicate greens or mushrooms less.

Finish and enrich

When vegetables are tender, if you prefer a smoother texture, use an immersion blender to partially or fully purée the soup directly in the pot, or transfer half to a blender and purée then return. Stir in 2 tablespoons heavy cream or coconut milk if using, then add 1 tablespoon chopped fresh herbs. Add 1 teaspoon lemon juice or vinegar if using to brighten flavors.

Seasoning & Garnish

Season the soup with 3/4 teaspoon kosher salt and 1/4 teaspoon freshly ground black pepper. Taste and adjust seasoning as needed. Simmer another 1–2 minutes to meld flavors.

Ladle a cup of soup into a warmed bowl or cup. Garnish with an additional pinch of chopped herbs and serve with a slice of crusty bread or croutons.