Chop vegetables such as carrot, onion, and green onion finely.

Place 2/3 cup of chopped vegetables in a bowl.

Drain the canned tuna and add it to the bowl.

Crack 3 eggs into the bowl and add milk, mirin, sugar, salt, and pepper.

Whisk the mixture until smooth, ensuring no large lumps remain.

Heat a pan with a thin layer of oil and pour a portion of the egg mixture.

Cook and roll the omelette in layers, repeating 5-6 times until all the mixture is used.

Shape the rolled omelette neatly and let it rest for a minute.