Wash and peel the potatoes and cut into small cubes. Read out the rocket, wash, dab dry and cut into strips. Peel garlic and onion. Finely dice onion, press garlic through a garlic press.
Tuna fish to pieces. Mix the pasta, rocket, basil, tuna, capers and vinaigrette, leave to stand for about 5 minutes and serve
Add cream to the rest of the soup and puree everything. Heat the soup again and season to taste with salt, pepper and parmesan. Arrange in a deep plate and sprinkle with remaining potato cubes and rocket.