can whole milk with corn starch be used to make caramel sauce?
@Brooke, I'm not sure you understand how caramel sauce is made. A mixture of sugar and water is cooked (much the way candy is cooked), basically till it reaches a thread stage - 110° to 112°C (230° to 234°F).  After it's finished cooking, the cream is stirred in. 

I'm not discussing method but only giving a basic idea. If you were to thicken it with cornstarch, you might make something palatable to put on desserts but it wouldn't be caramel. It's important to cook the sugar till it caramelized.  There's no brown sugar in it. You didn't mention that but others reading this in the future might think it's needed.

It's possible you could use evaporated milk instead of cream but there's no guarantee. I've not tried it. Yes, real caramel sauce is rich and sweet but that's the purpose of it and not a lot is meant to be eaten ...or often.