Heat a pan with olive oil. Put the tomatoes cut into slices or cubes in the medium-hot oil, add a dollop of butter to round it off. Seasoning, keep warm.
In the meantime, cook the pasta of your choice as instructed. Cut the mozzarella into fine cubes or strips. Wash, clean and dry arugula.
When the noodles are cooked, drain them. Put a dash of olive oil in so that they don`t stick together. Place quickly on the plate or in a bowl, mix in the tomatoes, rocket and mozzarella and top with grated or very thin slices of fresh parmesan.