It's the "cinnamon crisp coffee cake" from king arthur flour, and was a little bit of a pain to prepare, since you have to make the dough, the filling, the crumbs, and the glaze, but i can't argue with the results.
It's very rich, not overly sweet, super soft crumb, just really really great.
I also used 2% milk instead of buttermilk because I didn't have any, so I'm very lucky it turned out so well. I just had to bake it for probably 15 minutes longer because the middle just would not set.
Dang, I want a coffee and a slice