Sourdough teacakes/hot cross buns?
I've added sourdough starter to things like pancakes and waffles, but never hot cross buns. However I believe it would be very tasty as the sourdough would take some of the sweetness of the buns. I found this link about sourdough hot cross buns and thought it might be along the lines of what you were looking for https://sourdough.com/recipes/one-penny-two-penny