Clean the mushrooms and cut off the stems. Finely chop the garlic cloves.
Wash the rosemary sprigs. Now heat the oil in a pan and add the finely chopped garlic. After 2-3 minutes, the mushrooms are added to the pan and heated while stirring constantly. When the mushrooms have clearly lost their size, the rosemary sprigs are added to the pan and deglazed with balsamic vinegar. Now continue to cook until the balsamic vinegar is reduced to a kind of syrup. Finally, season with salt and pepper.