I am at my wits end. When I cook my pies, the tops crack, and the pastry, while flaky, leans toward sandy in texture. The crust does not have enough body. When it is cut, the pastry falls apart some. I use 3 cups all purpose, 8 oz shortening, 2 oz of butter (cold) and cold water. Combine fat in processor with half the flour and then the 2nd half of flour. Use 1/3 cup water or a little more. I also refridgerate the dough before using. I've tried different amounts of flour, fat and water. I've tried processing less and processing more. I'm using a commercial convection oven at 330 Fahrenheit. What am I doing wrong? Any suggestions appreciated.