swoon! I normally eat my burgers on lettuce or what's called 'flat out' wraps. Heck no...gonna try this with the mustard/onion deal as I like both. Never been to an 'In an Out' joint but have heard of them (sighing dramatically).
I think the key is to sear at a high temp the room temp meat on each side. I have a circulon 12" round pan that will work perfectly. Or my cast iron fry pan. Either way...I'm doing this soon. I'm totally salivating just reading this. Thanks DJ.