A delicious mashup of French Onion Soup and a great steakhouse burger, this recipe is a treat for anyone who likes a burger that feels a little over the top. A generous portion of caramelized onions cooks on the stove while a tender juicy meat patty cooks in the air fryer. The burger sauce features Worcestershire sauce, mayo, soy sauce, and Dijon mustard, which ties together the flavors coming through from onions.
Notes from the Food & Wine Test Kitchen
Making an indentation in the center of the burger patties prevents them from bulging when cooked.
Make ahead
Refrigerate caramelized onions for up to three days and gently warm them on the stove or in the microwave before using. You can also prepare the burger patties and refrigerate them for up to one day prior to cooking.