OK, you guys who go crazy with the rubs will think I'm nuts. I finally found a way to get a great seared burger that is medium rare. I get my burger from a butcher, so I'm not concerned about cooking it through. I've always been stymied, though, because by the time I get the burger nice and seared, it's medium well. I finally decided: Sugar is the answer! Until now, I've been strictly salt and pepper.
I made a pretty standard rub with garlic and onion salt, sugar, kosher salt, paprika and a bit of chipolte powder. Sprinkled it fairly lightly on 4 oz. burgers (yes, they're small, but I don't want to get huge). Got the mini to 500 degrees. Three minutes on one side, then flipped front to back and two minutes on the other. Lots of flames while turning. Perfect. Great sear and medium rare. You don't really taste the rub much.
Of all the cooks, brisket to ribs to pork butt and chicken, I've really been challenged by a great burger. I don't go in much for the fancy rubs because I'm all about the taste of the meat and whatever sauce the guest would like. I'm pleased.
Owner of a large and a beloved mini in Philadelphia