I made mini apple hand pies using a typical pie crust recipe…2.5 cups AP flour, 1/2 cup butter, 1/2 cup shortening, a little salt and sugar.  I made it in the food processor using butter, shortening, and water that I store in the fridge. The dough rested for hours in the fridge, was rolled to about a generous 1/8 inch, and the pies were frozen before baking. The crust is buttery and flaky and tender, not tough at all, but I feel that the texture is too crumbly and does not have the structural integrity that I would like. The 3” pies had large cracks across the tops and were a bit difficult to eat because they would break into two. What am i doing wrong? What is causing the cracks in the crust?

You might try to get a little more gluten development while at the same time relaxing it more to help prevent cracking.  To do this, you could process less when adding the fat to the flour so that it’s in larger pieces (less fat coats the flour, allowing more gluten to form) and then work the dough a tad more after adding the water.  To relax the dough, consider adding a little cider vinegar to the water (in addition to relaxing the rolled dough in the fridge).

You may also need to bake less if the crust was fairly brown, as even a little bit of overbaking can shrink a pie crust dramatically, contributing to cracking in a top crust.  The crust was vented, wasn’t it?

I can’t recommend Rose’s cream cheese flaky dough strongly enough, the flavor and texture is wonderful.  And, it’s available over on the blog.

I would conclude that you over mixed the butter/shortening a bit too much. Easy to do with the processor. You need some tiny balls of fat to roll out flat between sheets of flour to create layers.