Wash, clean, and finely chop the mushrooms. Peel and finely chop the onion.

In a pot, heat the olive oil and then add the onion. Fry for a few minutes, stirring occasionally.

Then add the mushrooms and pour in water (approximately up to ¾ of the height of the mushrooms). Bring to a boil and then reduce the heat. Cook covered until soft, which takes about 5-10 minutes. Stir occasionally. If necessary, add a little more water or pour off the excess just before blending.

Remove from heat and add yogurt. Season to taste with salt and pepper. Use a hand blender to blend everything until smooth and thick. If you find the soup too thick, add a little water and mix.

Serve on a plate.