Salt a pot of water and start boiling the rutabaga slices. Preheat your oven to 400F/200C.
While the rutabagas cook, make a sauce by melting the butter over medium-low heat in a separate pot. Whisk in the flour, continuing to whisk until smooth, then whisk in the half-and-half. Remove from the heat, add the sugar, cinnamon, salt and pepper, and eggs. Stir well.
Once the rutabaga slices are soft, reserve half of them, mash the other half with the cream sauce, then mix in the remaining slices.Butter an oval or round baking dish (a deep pie plate works fine), pour the mixture into the dish, sprinkle the bread crumbs over, and bake in the middle of your oven for 30-40 minutes, or until the surface begins to brown.