Hard boil the egg by placing it in the strainer basket with 500 gr of water in the TM. Put TM at varoma temp, speed 1, for 14 minutes. Remove egg and place under running cold water to cool.
Clear and quarter the shallot and cut the celery stalk into 4 pieces. Place in the TM.
Process for 5 seconds at speed 5
Strain the tuna to remove the water or oil it was packed in. Add to TM.
Process at speed 5 , reverse, for 5 seconds or until desired consistency is reached.
Turn out into a bowl. I find that it's easier to clean out the TM if the mayo is added separately.
Add the mayo, salt, and pepper.
Mix the mayo into the tuna with a spatula.
Add egg to the tuna. I like to see pieces of the egg white, so I use a safety grater through which I push the egg.
Stir to integrate the egg, check salt and pepper, and you're done