Mochizuki-san'chi no Yankee

When their mother passed away, the Mochizuki family's eldest daughter Yuka tried to take care of her father and siblings as best she could, but her cooking was just too awful. When Yuka's father accidentally tasted an amazing bento, he hired the person who made it to be a domestic helper. That person turned out to be Kuraku, the blonde-haired delinquent (but with the best grades) in Yuka's class! Based on the popular pixiv series!