Heat oil over medium heat.
Add butter and brown slightly.
Add sliced onions and cook while stirring for about 10 minutes or until onions just begin to caramelize.
Add Brown Sugar, Salt and Pepper. Stir well, reduce heat to medium low and continue cooking for 20-30 minutes.
When onions are caramelized, add the Beef Au Jus and Jim Beam Black Bourbon
Cook until onions have a nice brown color.
Remove from heat and cool slightly.
Place onions in food processor and pulse until smooth.
Combine in mixing bowl with mayonnaise and mix until smooth.