Place 12 baby potatoes in a pot. Add about 500 ml of water and 5 g of salt. Cook over medium-high heat for 5–7 minutes, then drain and transfer to a bowl.
Finely chop 2 cloves of garlic and set aside.
Heat olive oil in a skillet over medium heat. Cut the parboiled potatoes in half and place them cut-side down in the skillet. Cook for about 2 minutes until lightly golden.
Add 150 g of cleaned white mushrooms. Sauté over medium heat for 3–5 minutes, stirring occasionally, until the mushrooms are tender and the potatoes are golden.
Finely chop 1 green onion and set aside.
Add 1 tablespoon of unsalted butter to the skillet and let it melt. Add the minced garlic and sauté briefly until fragrant.
Season with salt and freshly ground black pepper to taste. Toss everything together until evenly coated in the garlic butter.
Transfer to a serving plate. Top with freshly grated Parmesan cheese and chopped green onion. Serve warm and enjoy!