Heat the butter and olive oil in a heavy medium saucepan over medium-high heat. Add the onions and sugar. Cook, stirring constantly, until soft and golden brown, 15-20 minutes. Season with salt and pepper. Stir in vinegar and simmer until the mixture is dry. Add the Gourmet Pepper Sauce. Remove the mixture from the heat and allow the onions to cool slightly. Mix the cream cheese until smooth in a large bowl. Fold in the sour cream and then add the onion mixture. Season with salt and pepper. Garnish with chives.