Heat 2 tablespoons of olive oil and 2 tablespoons of unsalted butter in a large pot over medium-high heat until the butter is foamy, about 1-2 minutes.

Add 1 chopped onion to the pot and sauté for about 5 minutes until soft.

Stir in 3 minced garlic cloves and cook for about 1 minute until fragrant.

Incorporate about 450 grams of sliced mixed mushrooms and sauté for 8-10 minutes until browned and tender.

Sprinkle 1/4 cup of all-purpose flour over the mushrooms and stir to coat evenly, cooking for about 1-2 minutes.

Mix in 1 teaspoon of fresh thyme leaves and allow to release their oils.

Slowly pour in 4 cups of vegetable broth, stirring continuously, and bring to a boil. Reduce to a simmer for about 15 minutes.

Remove from heat and let cool slightly before blending until smooth.

Return the blended soup to the pot over low heat and stir in 1 cup of heavy cream.

Season with salt and freshly ground black pepper to taste.

Warm the soup gently over low heat for about 5 minutes, stirring occasionally.

Garnish each bowl with freshly chopped parsley and serve hot.