I grind my own chuck making sure that there is a reasonable amount of fat included (the exact percentage is pretty hard to calculate). I prefer to cook it in thickish, hand-formed patties over charcoal on a Lodge cast iron grill (cast iron holds the heat best and therefore sears the meat better). Unlike Rick, I want flames–my ideal burger is blackened crispy on the outside but with a pea-sized bit of raw meat in the center.