If making your own pie crust, combine flour, sugar, and salt in a large bowl. Add 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 water gradually (or pulse with a food processor) until dough holds together when you pinch it between your fingers. Wrap dough with plastic wrap and chill for at least 30minutes.
Preheat the oven to400°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 pie crust to fit into 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 hot air to escape.
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.
IF MAKING AFULL 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.
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.
Store in in the fridge in an airtight container. Note: These pies freeze well. Freeze in an airtight container or Ziploc bag, will keep for up to 3 months.