6 tablespoons cold unsalted butter, cut into small pieces
3/4 cup solid vegetable shortening, cut into small pieces and chilled
5 to 6 tablespoons ice water
In a food processor, combine the flour, salt, lemon zest and cinnamon. Add the butter and shortening and pulse until the butter is the size of small peas. Transfer the mixture to a large bowl. Add the ice water and stir with a fork until the dough comes together. Divide the dough in half and pat each piece into a 6-inch disk. Wrap the disks in plastic and refrigerate 1 of them for at least 1 hour before rolling out. Put the second disk of dough in a sturdy resealable plastic bag or wrap it again in foil and freeze for later use. Thaw the dough without unwrapping it.