Dosa Kitchen’s ready-made batter | Lille Allen/Eater With its dosa batter, Dosa Kitchen hopes to educate people about everything dosas can do. But why do Americans still need an education? Open the fridge in many South Indian homes, and you’ll probably find a tub of dosa batter bubbling with fermentation. Perhaps it’s homemade, or it could be from the number of brands selling premixed batter in South Asian markets across the country. It’s a kitchen staple like anything else, unremarkable except to those for whom the dosa remains unfamiliar. Which, in America, is a lot of people. Dosa Kitchen wants…