These sure looked magnificent, but I was disappointed in a couple of aspects. The dough is excellent. When I made the filling, there was nowhere near enough to cover the rectangle. (I was following your instructions precisely, so I measured the dough to 16x20) My solution was to bulk it up with more 'butter.' I also added more cinnamon, 2.5 tsp seemed light. I carefully covered the surface, though I recommend using a rubber scraper or an offset spatula rather than spoon. Anyhooo. I baked them in a metal pan lined with a silicone sheet. I usually stay away from glass as it's a poor conductor of heat, and I wasn't worried about even cooking because I was using the convection setting in my oven. They came out looking incredible. I used a reduced amount of coconut oil in the frosting (I was low having just made some vegan butter :) ) and was glad of that because I prefer a less viscous result from using just the milk.
The thing was, when we dug into them, there was virtually no filling inside. It had either been absorbed somehow or leached out. There were in fact puddles of caramel on the silicone sheet. That said, my husband thought they were delicious, and they were really good. Next time I think I would actually cut back on the butter in the filling. Do you think that might keep the filling from sliding out?