Has anyone ever made caramel apples? I'm pretty sure that I messed this up. The recipe said to cook the butter, corn syrup, sugar and cream until the candy thermometer read 280 degrees. What do they mean by cook? Do I stir constantly, not at all, maybe a little here and there? What type of heat do I use? High, medium-high? My pan now has a black bottom and my kitchen is filled with a smokey smell. I can't imagine that this caramel tastes very good. Help!