The filling for this cake is traditionally a cinnamon and sugar mixture. For that filling, spread softened butter on the rolled out dough and sprinkle with cinnamon sugar.
I filled the cake with a cream cheese mixture which was 8 oz. softened cream cheese and 1/2 brown sugar combined.
You can fill this cake with whatever you like. You might try an apple pie filling or a praline filling. I’ve seen cakes with a banana filling and a caramel glaze. So many possibilities . . .
One note: It is best to plan ahead. Get your ingredients out early and bring everything to room temperature before you begin. Make sure the butter and shortening are soft so they will incorporate easily into the dough.