In a medium-size bowl, whisk together the flour, salt and (if using) the sugar, baking powder, and spices. Use a coarse cheese grater to grate the cold butter on top of the flour mixture. Place in the freezer for an hour or overnight.

Use your fingertips to work the butter into the flour, until the largest piece of butter is about the size of a smallish pea. Sprinkle on the cider vinegar, if using. Add the cream with one hand, a bit at a time, while working it in with the other hand. The hand that’s working it in should be held stiffly with fingers bent like claws. When there is enough cream, about half of the dough will be sticking together in large clumps.

Transfer the dough to a large flat surface such as a marble board or a silpat pad. Gather dough into a rough, rectangular mound. Beginning from farthest end, use heel of your hand to smear dough against work surface, away from you. Repeat until all dough has been worked. Gather dough together into separate sections for each crust, and shape each into disks. Wrap each disk in plastic, and refrigerate until cold and firm, at least one hour (more rest produces a more tender crust).

When you are ready to roll out crusts, dough may need to sit at room temperature for about twenty minutes to become malleable.

Note: When lining a pie pan, be sure to push the dough into place; stretching it will make the crust shrink.