In a large bowl or food processor, combine the flour, sugar, and salt.
Cut in the butter and shortening using your fingers, a dough blade, forks, or by pulsing in the food processor until the mixture becomes coarse and no pieces are larger than a pea.
In a small bowl, combine the water and vinegar. Slowly add to the flour mixture a little at a time until the dough comes together in a smooth ball.
Divide the dough in half and form each into a flat disc. Wrap in plastic and refrigerate 3 hours to overnight.
Preheat oven to 425 degrees F. Grease muffin tins with butter (this step may actually not be needed, but I always do it out of habit and for security).
On a lightly floured surface, roll the refrigerated dough into a sheet between 1/8 and 1/4 inch thick. Use a 4 inch round cutter to cut out circles of dough. Push each circle down into the prepared muffin tins. Place the muffin tins in the refrigerator while you prepare the filling.