What can be substituted for the pastry?
I really don’t know how you’d ‘synthesize’ puff pastry in a way that it’s not ‘bread’. But if your concerns are gluten and carbs, there are low-carb alternatives to pie pastry:
http://fitlivingfoodies.com/recipe-archive/gluten-free-crust-recipe/
You can also roast asparagus wrapped in bacon:
http://www.food.com/recipe/bacon-wrapped-asparagus-167834
If it’s because of carbs you can use carbquick. It’s like bisquick with super low carbs. I use it for everything.
RR,
Cauliflower is a good substitute
http://detoxinista.com/2012/01/the-secret-to-perfect-cauliflower-pizza-crust/
http://kirbiecravings.com/2016/07/cauliflower-bread-buns.html
http://www.jocooks.com/healthy-eating/cheesy-cauliflower-breadsticks/
http://www.huffingtonpost.com/2014/08/19/paleo-recipes-with-cauliflower-delish_n_5689172.html
Do you do potatoes? What if you baked a bunch of medium sized russets just shy of done, then halved them, pressed them down to make little patties with the peel still as the crust, then put the Fontina cheese and (already sliced shorter) asparagus on each potato patty?