Transfer the sweet potatoes to the bowl of an electric mixer fitted with the paddle attachment. With the mixer on low, slowly add the half-and-half, orange zest, orange juice, cayenne pepper, 1 tablespoon salt, and 1 teaspoon black pepper. With the mixer still on low, add the butter, 1 tablespoon at a time, until incorporated. Taste for seasonings and mix until smooth. Serve hot.