When Jaejoong was a child, his mom used to own a restaurant and was working the whole day long, Jaejoong said that he used to come home and cook lunch for himself cuz nobody was home and in summer he used to help her mom in her restaurant and that's how he picked cooking skills at very first, later he had to live with his members and cook for them all the time, rest is history cuz look at how amazingly good cook he is, in Jaechingu too.