Boiled? Baked? Steamed? Fried? Should you follow a reciepe for preparing bats (assuming there is such a thing) or long pig? What kind of wine would you serve? Would Robin make a good appetizer?
The only recipe for bat I could find doesn’t seem so great for Batman, so I’d go with the long pig angle. Being a flexible young man, Robin should quite clearly be saved for after-dinner entertainment.
Make sure you’re not using the Flying Fox bats from Guam. Their diet, high in seeds of the cycad plants, concentrates neurotoxins in their flesh. This can result in a number of neurologic diseases manifesting in those that eat them.
In his costume and smokin’ hot.
:: d&r ::
Make that OUT of his costume, and I’ll second that.
Well-cooked, preferably while in a giant-sized hour glass that is slowly filling with sand and is gradually getting heavier as the sand pours into the bottom half (containing Batman and Robin), which sinks the hour glass closer and closer to a large fire burning underneath.
Anything ridiculously giant-sized will do, I suppose.
The beliefs expounded thus far in this thread are all HERESY.
I’m surprised that nobody’s recommended fava beans and a nice chianti yet. 
Fava beans and a side of ch- uh…
beaten.
With a side of Robin.
Topped with a nice Alfred-O sauce…