Cook the macaroni in boiling salted water for about 12 minutes. Meanwhile wash tuna, dab dry and cut into small pieces. Sprinkle with lemon juice. Clean and wash the leek and cut it into rings. Heat 2 tablespoons of oil in a pan.
Brown the tuna in it, take it out. Add the leek to the frying fat, fry briefly. Add tomatoes and olives. Season to taste with salt, pepper and rosemary. Add the tuna. Wash parsley and chop coarsely. Drain macaroni. Add 1 tablespoon of oil and the parsley to the pot and toss the macaroni in it. Arrange the pasta with the sauce on a plate.
Add the tuna. Wash parsley and chop coarsely. Drain macaroni. Add 1 tablespoon of oil and the parsley to the pot and toss the macaroni in it. Arrange the pasta with the sauce on a plate. Garnish as you like with fresh rosemary and lemon slices