Clean the mushrooms gently with a damp paper towel instead of soaking them in water. Mushrooms absorb moisture very quickly, and too much water prevents proper browning.

Slice the mushrooms evenly so they cook at the same rate.

Heat olive oil and butter in a large pot over medium heat.

Add the chopped onions and cook for about 5 minutes until soft and translucent. Stir occasionally so they do not brown too quickly.

Stir in the garlic and thyme leaves. Cook for about 1 minute until fragrant.

The kitchen will already start smelling amazing at this point.

Add the sliced mushrooms to the pot.

This step is the heart of the recipe, so do not rush it. Let the mushrooms cook slowly for 10 to 15 minutes until they release their moisture and begin caramelizing.

The mushrooms should become golden brown and deeply flavorful.

Pour in the vegetable stock or chicken stock.

Bring the soup to a gentle simmer and cook for another 10 minutes to allow the flavors to blend together.

Use an immersion blender directly in the pot or carefully transfer the soup to a blender.

Blend until smooth and velvety.

If you prefer a chunkier texture, blend only part of the soup.

Return the soup to low heat and stir in the heavy cream.

Add salt, black pepper, and lemon juice.

The lemon juice may seem small, but it brightens the entire soup beautifully.

Ladle the soup into bowls.

Top with chopped parsley, cracked black pepper, and a tiny drizzle of truffle oil if desired.

Serve hot with toasted bread.