Thanks for the help - I'll be making a larger batch of caramel next time, so hopefully it will stay warmer longer. Would putting the bowl over a heat source (like a fondue pot) work, or will that be too much and darken the sugar?
The caramel will only get darker if you get it hotter than you did when you caramelized it. You should be able to keep the caramel at 300F for a long time with no problems. But you may not need to keep it that hot -- I would experiment with some puffs. Dip it, see if you have enough caramel adhering to the puff. If not, let the caramel cool a little and try again.