Tuna and Potato Salami

This is a Marcella Hazan recipe that we made over 390 years ago for the first time, but haven't made in at least a decade until just recently. It is simple, not much to look at, but delicious. Use tuna in oil if you can get it. 1 medium potato 14 oz. tuna in oil 1/4 c. grated parmesan cheese 1 egg plus 1 egg white salt and pepper to taste Poaching Broth 1/2 onion sliced 1 stalk celery 1 carrot handful of parseley 1 c white wine salt Aoili 1/2 c. mayonnaise 1/2 lemon zested and squeezed 2 Tbs. crushed and chopped capers splash of fish sauce or 1/2 anchovy shredded sliced black olives salt and pepper to taste Boil the potato until soft through and rice through a potato ricer. Flake the tuna, and add the egg, cheese, salt, and pepper. Divide into 2 equal amounts and form into logs. Moisten 2 pieces of cheesecloth to wrap up the tuna logs (about 1/4 of a store bought package of cheesecloth for each log). Roll up and tie the ends with twine. Put in the poaching broth and bring to a boil. Reduce heat and simmer for 45 minutes, then drain and cool the logs in the fridge. Best after 24 hours. Unroll and discard cheesecloth. Slice 1/4-1/2 inch and top with the mayo sauce.