Preheat the mini waffle maker on medium for about 5 minutes.

Whisk the egg in a mixing bowl until frothy, about 1 minute.

Add the drained tuna, shredded cheese, and salt to the whisked egg. Mix until well combined.

Sprinkle shredded cheese onto the hot waffle maker to create a crispy base.

Spoon half of the tuna mixture onto the hot waffle maker and cook for about 4 minutes.

Check for doneness; it should be golden brown and crispy.

Repeat the process with the remaining tuna mixture for the second chaffle.

Allow the chaffles to rest for 1-2 minutes before serving.