Ingredients
-
4 tablespoons unsalted butter
-
2 large onions, peeled and thinly sliced
-
Kosher salt and freshly ground black pepper
-
1 pound ButcherBox Ground Beef, formed into 4 (4-ounce) patties, roughly the size and shape of 1 slice of bread
-
4 tablespoons canola oil
-
8 slices seeded rye bread
-
4 slices Swiss cheese
or 4 slices American cheese
-
4 more slices Swiss cheese
or 4 more slices of American cheese
-
Dijon mustard for serving
Step By Step