Can I boil a yogurt marinade if I add cornstarch? I'm making tikka masala tonight, and the chicken is marinating in a yogurt mixture. I've already made a sauce to eat it with, but I was wondering if there was a way to bring the marinade to a boil so that I could safely consume it too.

I heard that adding cornstarch to yogurt helps keep it from splitting, but would that be enough if it has to come to a rolling boil anyway?
Good news! There is no reason to bring the marinade to a rolling boil as a simmer will siffice. Chicken and other items that have been in contact with raw chicken are considered safe at 165 degrees (See http://www.foodsafety.gov/keep/charts/mintemp.html). A simmer is generally about 180. If the sauce breaks however, you are correct that a cornstarch slurry should pull the marinade back together no problem. Happy cooking!