I've been thinking about making this recipe for weeks, and finally did. I'm not sure if I didn't put enough Nutella, but I didn't get Nutella in every single bite as promised. I decided to add a little spoonful of Nutella on top of each muffin after adding the cinnamon/sugar/butter topping.
The original recipe can be found here. Her photos are much more drool-worthy. Make these!