Maison Kayser's version ($6.95 for an individual portion, $28 for full size) is quite different from Epicerie Boulud's. For starters it's sold as an individual round mini cake with crust on all sides, not a cake slice. Then there's the lightness of the crust. It's far less dense than the Boulud offering and most King Cakes I've eaten over the years, something like the crust you'll find in an apple turnover.
That means if you eat the entire cake in one sitting, oh I don't know, for breakfast, you don't feel too stuffed afterward. But it's available for a limited time only, so get it now.