By Logan Mahan Luxury burgers are nothing new in the world of fine dining, from Gramercy Tavern’s off-menu burger – once limited to just 40 orders a day – to Las Vegas’ $5,000 Fleur Burger boasting wagyu beef, foie gras, truffle, and a bottle of 1995 Chateau Petrus to wash it all down. It was a considerably cheaper luxe burger – the $28 Black Label at Greenwich Village’s Minetta Tavern – that initiated chef Ashish Alfred to the genre, when, as he tells it, as a broke culinary school student, he “did what any good academic would do” and waited patiently for his dad to come to town and treat him…