Wash the Jerusalem artichoke thoroughly and slice thinly; cut the tofu and tuna into bite-sized pieces.
Add cooking oil to a pan and first stir-fry the Jerusalem artichoke.
When the Jerusalem artichoke is halfway cooked, add the tofu and fry until golden brown.
Add the tuna and seasonings (soy sauce, gochujang, minced garlic, sugar, pepper, etc.), then mix well.
Cover with a lid and simmer on medium heat for 5 minutes.
When the sauce thickens, transfer to a plate.