For the Burgers
Pat bison into 4 burgers, and place on a hot grill. Grill 3–4 minutes on each side for medium (bison is a lean meat, so medium is recommended).
For the Onions
Combine oil and butter in a saucepan, over high heat until butter is melted.
Sauté the onions and cook for about 3 minutes. Remove from the flame and carefully add the bourbon (use caution as the mixture could flambé when returned to the heat), reduce heat and continue to simmer about 10 minutes, until the juices are slightly reduced.
Build the burger with your favorite accompaniments, top with the caramelized onions, sprinkle with bacon and drizzle 1½ teaspoons sorghum over the top.