Makes 2 cups
2 large yellow onions
4 Tablespoons unsalted butter
¼ cup vegetable oil
¼ teaspoon ground cayenne pepper
1 teaspoon kosher salt
½ teaspoon freshly ground black pepper
4 ounces cream cheese, room temperature
½ cup sour cream
½ cup good mayonnaise
Cut the onions in half, and then slice them into 1/8-inch-thick half-rounds. (You will have about 3 cups of onions.)
Heat the butter and oil in a large sauté pan on 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.
Place the cream cheese, sour cream, and mayonnaise in the bowl of a food processor and pulse until smooth. Add the onions and mix well. Taste for seasonings.
Serve at room temperature.
Thanks to Carol L for getting this to me!