You’ll want to pull your server aside and whisper your request for the off-the-menu burger. It’s a triple-cream Epoisse cheese and caramelized onion-topped burger on an English muffin. And it's only available in a very limited number each night.
Époisses is a creamy, pungent unpasteurized cow's milk cheese from Burgundy, France and is pronounced "eh-pwahss". The cheese is mixed directly into the burger's sirloin patty.
Given the distinct flavor profile of Heirloom's burger, Straus and his staff are right to think that standard ketchup and mustard aren't entirely appropriate. Instead, both the top and bottom bun on the burger were spread with a sweet and slightly winey onion jam, with a little bit of arugula sitting beneath the patty. The English muffin bun from Sconehenge had been buttered and given a long sojourn on the griddle until it developed a rich and crunchy outer lip. The end result was a very well-composed burger.