Wash and finely chop carrot, green onion, and shiitake mushrooms. Drain the oil from the canned salmon.

Combine chopped carrot, green onion, mushrooms, and salmon in a bowl. Season with salt and pepper, then mix thoroughly to create the filling.

Slice onions into 0.5cm rings, removing the inner parts to create hollow rings. Reserve smaller pieces for other recipes.

Coat onion rings with flour to help the filling adhere better.

Fill the onion rings with the prepared mixture, pressing firmly to ensure no gaps. Coat both sides of the filled rings with flour again.

Beat 2 eggs to create an egg wash.

Dip the filled onion rings into the egg wash, ensuring they are fully coated.

Heat a pan over low heat and add cooking oil. Place the onion rings in the pan and cook until the filling is thoroughly cooked and the rings are golden brown.

Flip the onion rings and cook the other side until golden brown and fully cooked.