Maybe you're thinking of baba ganoush, which is a dip with a charred eggplant and tahini base. I've made it with eggplant broiled in the oven, and it's fine, but I'm sure the taste is different if they're charred over a flame. (Even though you discard the charred shell either way.) That said you could easily accomplish that with a kitchen torch, the kind also used to finish creme brulee or (if you have a big torch) sous vide meats.
There's also a Balkan variation of baba ganoush without tahini, just cooked eggplant, onion and sunflower or olive oil. It's boringly called 'eggplant salad' in my country. The Greek version is very similar and BBQing the eggplant makes even tastier. Another variation of this dish also exists in the Carribean, where it's called baigan choka.
Heat a pan, until a small amount of ghee/butter melts when placed on it. Place the roti on the pan, and cook each side. You will know that it is done when the roti slightly puffs up.
True skill is in making rotis which stay soft in a hotbox.