Clean the mushrooms and remove the leaves, pieces of wood and the remains of the soil. Slice them into pieces.
Heat the butter in a pan and saute the porcini until the excess water evaporates.
Heat three tablespoons of olive oil in a big cooking pan. In the meantime, dice the garlic and the onion. Add the onion and stir until it looks golden yellow, tender and translucent.
Add the rice to the pan and toast it for a few minutes.
Add sour cream and garlic. Finally, bring in the stir-fried porcini mushrooms. Make sure that all ingredients combine.
Sprinkle with a pinch of salt and black pepper and pour in a glass of water (or wine). The rice should be covered with liquid, but do not add more than one small glass at a time.
When almost boiling, reduce to the lowest heat. Stir frequently.
Cook for about 15-20 minutes. Just before the rice is cooked, add fresh parsley, turn of the heat and let it rest (covered with a lid) for few minutes.
Sprinkle with parmesan cheese and serve with a glass of white wine.