Kyou no Ashura Meshi

Omori Sizuka is a high school girl who loves to eat and but gets bullied for her weight. One day, she discovered that Akira Kurose, aka "Ashura-kun," the toughest delinquent at school, secretly enjoyed cooking. The next day at lunchtime, Akira summoned Sizuka to the rooftop and asked her to eat his homemade bento, in exchange for keeping her mouth shut.

(Source: Kadokawa, translated)