Wash and peel the mushrooms and potatoes. Wash the greens and wet them with a napkin.
Cut the potatoes into slices and fry in olive oil with a sprig of rosemary. Season with salt and pepper to taste. To make the potatoes more crispy, fill them with cold water for 30-60 minutes, so that the starch goes into the water. The older the potatoes, the less they need to be soaked.
Cut the mushrooms into slices and fry. Season with balsamic vinegar in a separate bowl.
Put the arugula on the dish, top with the fried potatoes and mushrooms. Season with pesto sauce.