Mushroom and potato soup

INGREDIENTS FOR 4
500 G MIXED MUSHROOMS, BUTTON AND OYSTER
500 G POTATOES
1 ONION
EXTRA VIRGIN OLIVE OIL
SALT
PEPPER
MEAT OR VEGETABLE STOCK
BREAD CROUTONS
I clean and briefly wash mushrooms.I thinly slice onion.I slice button mushrooms. I slice oyster mushrooms.I peel potatoes.I finely dice them.I sauté onion in oil and add potatoes.I stir in mushrooms.After a few minutes, I add stock. I cook about 30 minutes until potatoes are done and stock absorbed. Avoid excess stock so soup is not thin; reserve some to add if needed. I hand-blend and add ground pepper.The soup should be smooth, thick and creamy.I serve with toasted bread croutons and oil.