A croissant with Nutella combines the best of both worlds: the lightness and butteriness of a croissant with the rich, chocolate-hazelnut flavor of Nutella. No chocolate cake does better.
Buy or bake the croissants according to description on the package.
Have each person spread their own croissant. That way, everyone determines their own amount of Nutella.
You can cut the croissant open and spread the Nutella on top. Personally, I find it easier to spread the Nutella on the bottom and eat the croissant upside-down.