For the salad you will need mushrooms.

Hats cut into thin slices. The onions I used onions, it is better to use a red onion. Cut onion into thin half-rings. For the sauce, mix the vinegar, oil, salt and pepper. In a bowl fold the cut cap and onion and cover with sauce. Mix well, cover the bowl with film and put overnight in the fridge.

Walnuts chopped. On a plate put the arugula, it put the mushrooms with onions, sprinkle with chopped nuts.

Our salad is ready!