I think we're still figuring out what the best foodstuff for this is
. Anything solid but oily is a good bet. Here's what I know:
1. Do not use peanuts. You should not see these at competition because of allergies.
2. Do not use marshmallows. They may ruin your device.
3. Potato chips burn but not anywhere near to completion.
You could read back through the topic for some ideas.