Combine cheese and cornstarch in a bag. Shake to make sure cheese is coated with cornstarch.
In saucepan carefully heat buttermilk until warm. Do not cover or boil.
Remember to stir constantly from now one. Add a handful of cheese, keeping the heat medium (do not boil), when melted add another handful. After all the cheese is melted and bubbling add a dash of nutmeg and pepper. Transfer to fondue pot and keep warm over fondue burner.
Note: If fondue becomes too thick add a bit of warmed buttermilk. If it separates combine 1 T cornstarch and 2 T buttermilk and stir into fondue.