1. Fill a large pot with cold water, add salt and bring it to a rolling boil over high heat. Add the potatoes and boil until tender.
2. While the potatoes are still hot add cream, 3 tablespoons Plugra butter, eggs, salt, pepper, nutmeg, and baking powder. Mash the potatoes until smooth. Let cool to room temperature. Gently fold in the remaining butter until pieces are evenly distributed.
3. Preheat oven to 350°F.
4. Transfer potato mixture to piping bag fitted with ½-inch star tip (you can use a gallon size baggie with snipped off corner) and pipe eight 4-inch wide mounds of potatoes on baking sheet.
5. Spray the tops of the potatoes lightly with butter flavored cooking spray and bake until golden brown, about 15 to 20 minutes.