Put the diced rutabaga in a large pan and cover generously with water. Bring to the boil, lower the heat and simmer for about 20 minutes until tender. Remove the pan from the heat and leave the rutabaga to cool in the water for about 30 minutes.
Drain well and mash the rutabaga.
Preheat the oven to 350 F.
Grease a deep, ovenproof dish with butter.
Pour the cream into a bowl, add the breadcrumbs, nutmeg and salt and mix together.
Add the beaten eggs.
Add the cream mixture to the mashed rutabaga and mix together.
Spoon the mixture into the prepared dish and dot the surface with the butter.
Bake in the oven for about 40 minutes until lightly browned. Serve hot.