When ready to bake, preheat oven to 375°F.
Pour melted butter into a 9x13-inch baking dish. Swirl around so it covers the bottom of the baking dish.
Arrange cinnamon roll pieces in baking dish.
In a mixing bowl, whisk together eggs, heavy cream, vanilla, cinnamon, sugar, and nutmeg. Pour over cinnamon rolls.
If making ahead: cover dish with foil and chill until ready to use, up to overnight.
When ready to bake, bake until rolls are cooked through but soft in the center, 30-35 minutes.
Remove from oven and let cool 10 minutes.
Pour icing from cinnamon roll package over casserole, serve, and enjoy!
