From Marcella's Italian Kitchen: "Canned tuna is a familiar ingredient in pasta sauces. Although I was once very fond of it, there was a harshness to the taste of tuna sauces, both other cooks' and my own, that began to trouble me. It took a long while, as my dissatisfaction grew, for me to identify its cause. At last I knew: Cooking altered tuna's taste. I looked for other ways to make a sauce that did not require cooking the tuna. The one that pleased me most is derived from the buttery sauce described [elsewhere in Marcella's Italian Kitchen]...I added garlic, egg, parsley, cream, and Parmesan, mixing everything by hand rather than in a processor to obtain a grainier, more interesting texture." —Food52
Drain the tuna of all its oil and put it in a mixing bowl.
Add the garlic, parsley, egg, butter, cream, salt, liberal grindings of pepper, and the 1/2 cup of grated cheese. Mix well until all the ingredients are thoroughly amalgamated, using a fork to break up and mash the tuna. Taste and correct for salt and pepper.
Drop the pasta into a pot of abundant boiling salted water and cook until it is done but firm to the bite, drain, and toss immediately with the tuna mixture. Serve at once, with additional grated cheese available on the side.