Years ago, while studying at Delhi University, a few friends and I were regulars at a small eatery near our campus. We went there for the usual student combination of cheap food and generous portions, with very little curiosity about how the food was made. I was particularly fond of its kadhi—the tangy, yoghurt-and-besan-based yellow gravy that is a staple in kitchens across Delhi and Punjab. I could easily put away several servings.