In a large bowl place the flour, sugar, baking powder and salt then whisk together.

Next add the sourdough starter and cold butter. Cut in with a pastry blender or two forks until the mixture looks like sand with a few larger pieces of butter.

Add the egg yolk and whisk it into the rest of the mixture. It should now hold together if you squeeze some in your hand.

Now cover and leave to ferment at room temp for about six hours. Or you can skip this step and go straight to making the whole thing.

Place the cherries and Maple Syrup in a medium sauce pan. Bring to a low boil over medium heat.

Mix the water and tapioca in a small bowl until the tapioca is dissolved in the water.

When the cherries are cooked and soft, slowly pour the tapioca water into the pan while whisking.

After the tapioca water is added continue to cook until thickened. Remove from pan and cool.

Preheat the oven to 375*F.

Line a 9x13” baking pan with parchment paper, then lightly grease that parchment paper.

Place the shortbread mixture in to the prepared pan but keep two cups of it for topping with.

Using a small piece of parchment paper, press the shortbread mixture into the pan firmly and evenly.

Add the prepared cherry pie filling and spread evenly over the shortbread crust.

Crumble the remaining shortbread mixture over the top of the cherries.

Bake for approximately 45-55 minutes or until the filling is bubbling and the topping is golden brown.

Cool in the pan for an hour then carefully remove to a cooling rack, for firmer bars and easier slicing transfer to the fridge to cool even further.

Slice and enjoy!