Fry thinly sliced white onion in olive oil. Add your beef strips and cook till brown on medium heat. In the meantime prepare your peanut sauce. Combine your peanut butter with water, soy sauce, vinegar, sugar, pepper. Mix with hand blender. Add chopped chives at the end. Pour half of the sauce over the beef strips. Sauce will thicken up. Then pour over your other half of the sauce and switch the stove off. Add your cashew nuts and serve with cous cous.