Combine the flour, sugar, and salt in a large bowl. Add the butter (or lard/tallow) and use a pastry blender or two knives to cut into the flour until you get pea-sized crumbs(alternatively use a food processor). Stir in the water gradually (or pulse with a food processor) until the dough holds together when you pinch it between your fingers. Wrap the dough with plastic wrap and chill for at least 30 minutes.
Preheat the oven to 400 degrees F. Grease a standard 12-cup muffin tin or mini tart tins.
Roll 2/3 of the pie crust out onto a floured surface to 1/8 inch thickness. Cut circles out of the pie crust to fit into the tins. Roll out the remaining pie crust to the same thickness and cut out circles for lids, or star shapes, or lattices (whichever you prefer). If using circles/lids to fully cover the pies, cut a slit in each pastry lid to allow the hot air to escape. IF MAKING A FULL SIZE PIE: Preheat to 375 F and bake it for 15 minutes, then reduce the heat to 350 F and bake for another 30 minutes or so.
Carefully press the pie crusts into the tins and fill them with mincemeat then top with the pie crust lids, stars, or lattices and press the edges together to seal them. Lightly brush the tops with milk or an egg wash.Bake the pies for 10-15 minutes or until golden brown. Carefully remove them from the muffin or tart tins, transfer them to a wire rack and sprinkle with powdered sugar.
Mince pies are best served gently warmed. They can be eaten with your hands or with a spoon if served with cream or even ice cream if you like. Stored in an airtight container, will keep for up to 4 days. Note: These pies freeze well. Freeze in an airtight container or ziplock bag, will keep for up to 3 months.