Cider Vinegar Tart

I was going to call this a “pie” but couldn’t resist the pun. The recipe apparently originated as a pie, and most versions I can find seem to come out of heartland America from an age when lemons would have been an uncommon find in the plains states. The method here is customarily used for a tarte au citron, a lemon tart. Critical to the outcome of this simplest of all pies is the use of a good vinegar—the tart is not worth making with bad vinegar. Otherwise, it’s better to use lemon