Step 1

Heat the butter and oil in a large sauté pan over medium heat. Add the onions, cayenne, salt, and pepper and sauté for 10 minutes. Reduce the heat to medium-low and cook, stirring occasionally, for 20 more minutes until the onions are browned and caramelized. Allow the onions to cool.

Step 2

Place the cream cheese, sour cream, and mayonnaise in the bowl of an electric mixer fitted with the paddle attachment and beat until smooth. Add the onions and mix well. Taste for seasoning and serve with potato chips.