Thinly slice the onion. Peel and cut the squash into cubes.

In a saucepan, sauté the onion in a little olive oil. Once it’s golden, add the squash. Season with salt and pepper, and add 1 sprig of thyme.

Pour in the white wine and cook until it’s absorbed. Add the milk and enough water to almost cover the vegetables. Cook for 15 minutes.

Rinse the oyster mushrooms. If any are large, cut them in half lengthwise. Heat a little olive oil in a skillet and sauté the mushrooms. Season with salt and pepper, and keep warm.

Blend the soup. If it’s too thick, add more milk or water. Serve in bowls and top with a few oyster mushrooms.