Drain tuna and add it to a large mixing bowl. Flake the tuna with a fork, ensuring there are no large chunks remaining.

Add eggs, breadcrumbs, and grated Parmesan cheese.

Season the mixture with salt and freshly ground black pepper to taste.

Using clean hands, thoroughly combine all ingredients until they form a cohesive and dry mixture.

Transfer the resulting mixture onto a sheet of baking paper and shape it into a meatloaf. Close the ends like a candy, then wrap the meatloaf again in two sheets of aluminum foil.

Place the meatloaf on the bottom of a pot and cover it with cold water. Bring it to a boil with the lid on. Count 40 minutes from when it starts to boil, then drain the meatloaf and let it cool completely.

Let it rest for an hour in the refrigerator.

Carefully transfer the polpettone to a serving platter and slice it into 1 cm (1/2 inch) thick pieces.

Serve your tuna meatloaf at room temperature, accompanied by a crisp green salad or roasted vegetables, or arrange it on a platter, garnished with lemon wedges and fresh herbs.