Preheat oven to 400 degrees.Place peeled/diced potatoes into a large stove-top pot and cover with water and lots of salt.Boil potatoes on high for 15 minutes or until they are fork tender.Drain potatoes; mash potatoes with butter, half n half and slowly mash in the egg yolks.Add salt, pepper and nutmeg.Fold in cheddar cheese.Place the mixture into a piping bag with a tip (you can also use a zip top bag by cutting off a small corner and using a decorative tips.Pipe potatoes onto a cookie sheet covered with parchment or a non-stick baking mat.Cook for 20-30 minutes until they just start to turn brown. (I watch them carefully at the 20 minute mark.)Remove from oven and cool for 5 minutes.