I don’t think I’ve ever seen a crumb topped dessert and been able to pass. I made apple butter bars with whole wheat flour, which added a nice nutty depth to the bars.
Here’s a non-recipe for you:
Shortbread base (sub whole wheat for regular flour). Save some of the base for the crumble topping. Slather with apple butter and a few thin-sliced apple slivers, more apple butter, and crumble topping. Bake until done, about 40 minutes.