Cook the pasta in salted water according to the instructions on the packet.
Meanwhile, finely dice the onion and garlic. Drain the olives well and cut into rings.
Heat the oil in a pan and fry the onions in it until translucent. Then add the tomato paste and roast. Drain the tuna, add to the pan and chop. Add the olive rings and garlic and deglaze with the milk. Season everything and let simmer for 5 minutes.
Drain the pasta, add to the pan and fold into the tuna mixture.
Pour the contents of the pan into a baking dish, sprinkle with the cheese and bake in the preheated oven for 10 minutes until the cheese has melted and is slightly browned.