Black Coffee (NAKANO Emiko)

Black Coffee (NAKANO Emiko) manga summary:

From Aerandria Scans: How does a girl declared by her childhood friend to be gloomy and anti-social transform into a cutie “as sweet as sugar” and every boy’s dream? And does every boy really dream of girls “as sweet as sugar”? Or is the rich and deep taste of coffee better than sugary glitter? The story of a girl who may not be sweet, but sure is as addictive as black coffee!