Anatomy of a Rhubarb Horn

Kristine, this one's for you:

One of my minor assignments here in Copenhagen has been to find out how to make this particular pastry. These rhubarb horns have one of the most complex flavor combinations I've ever found in a pastry. Naturally, I've been eating several horns every week in order to properly analyze the components, which are:

• Soft, yeasty pastry dough, probably similar to cinnamon roll dough. Made with whole milk, yeast, flour, sugar, melted butter, and maybe an egg.
• Inside, there is a layer of custard, but it must be mixed with a small amount of almond paste, because there is a faint almondy flavor, and nutty texture.
• Also inside, is a slightly tart layer of rhubarb (no strawberry) compote. Amazing!
• Lastly, on top there are sprinkles of sugar and sliced almonds, and maybe some sliced filberts, that get crunchy together while baking.

This is the first of my non-photographic blog posts, but since a substitute camera arrived on Friday (thanks Mick and Jess Yu) I may post some more photos soon.