Naturally, I can't remember where I got this recipe, Epicurious, I think...not sure. Anyway, it calls for an egg and cornstarch. you bring the milk (w/chocolate, cocoa, and sugar) to a simmer, add the beaten egg and two tsp cornstarch and stir til a custard forms. then you take it off the heat and add 1c yogurt. let cool, put in ice-cream maker and etc. But the custard always ends up a bit lumpy and the frozen end product has these hard lumps. I really do think I'm stirring but perhaps I'm missing something or just not doing it right? I know there's a ton of ice cream mavens out there, so please help!