Dice the onions Heat the butter and oil in a large saute pan over medium heat. Add the onions, cayenne, salt, and pepper and saute for 10 minutes. Reduce the heat to medium-low and cook, stirring occasionally, 20 to 30 minutes until they are browned and caramelized. Allow the onions to cool.
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 seasonings. It is best when stored obver night in the refrigerator so the flayors meld. Serve with good crakers or homemade crostinis.
Make this two days before your party, and you'll be all set! EASY!!!