INGREDIENTS
•
2 tablespoons unsalted butter
•
1 large yellow onion, sliced
•
Kosher salt and freshly ground pepper
•
1/2 cup dark brown sugar
•
1/3 cup whiskey
•
1 1/2 pounds ground bison
•
1 white onion
•
2 tablespoons vegetable oil, plus additional for grill
•
4 sesame seed or poppy seed rolls, split
•
4 lettuce leaves