Sauté ham in 2 TB of the butter....add chopped onion of choice and fresh thyme( dried may be used, but fresh is recommended) Sauté until onion is translucent.
In a separate saucepan warm softened cream cheese and heavy cream, stirring often until well combined and creamy. Add 1 cup of the cheese, whisking to combine and smooth.
In a greased baking dish layer your prepared turnips, cover with the ham/onion herb mixture....spread your cheese sauce evenly over the top. Stir well to combine. Mix in additional cheese. Dot with the remaining butter.
Cover with foil. Bake 30 minutes.
Remove foil and bake and continue baking for 45 minutes.