AMy ganache I just made is sitting on the counter but is getting like an oily film on top of it... Something doesn't look right... Did I over heat it? Can it be fixed?

AProbably just a skin. Stir it up put plastic wrap on the top covering the surface. That may help with that

AThanks! Ill try that!

If your ganache is separating that means you overcooked the chocolate or it got too hot.  All you need to do is melt some regular chocolate and add it.  Just a few ounces at a time and it will come right back together.  If you don't have more chocolate you just need to wait for the ganache to not only cool, but for the chocolate to calm down, so to speak, and it will come back together.  Do not refrigerate it, just leave it out.

Good luck!

AThe last time I made dark chocolate ganache the same thing happened to me. Not. Cool. What did I not do to fix it? Reheated and tried to re emulsify. No luck. Tried to bring it back to temper by seeding... Nope. Divided in half, cooled one batch, reheated the other and then combined trying to get the fat crystals to disperse. Nope. Very LAST RESORT (because it will change the consistency of your ganache) was to reheat to between 90-94F and then add corn syrup. That fixed it, and it reemulsified BUT the extra liquid meant my ganache wasn't great for going under fondant anymore as it was too soft and temperamental (I may have added too much. You need the minimum amount of liquid to redisperse the fat crystals)... and still had a slightly grainy texture. I ended up using it as a filling and crumb coat.

If you know how to temper chocolate using the seeding method, I would try that first.

Good luck.