• Step 1: In a food processor, pulse the flour, butter, sugar, and salt until the mixture resembles coarse crumbs. Gradually add the ice water and pulse until the dough just begins to come together. Do not overmix.
• Step 2: Turn the dough out onto a lightly floured surface and gather it into a disk. Wrap in plastic wrap and refrigerate for at least 30 minutes (or up to 3 days).
• Step 3: Preheat your oven to 375°F (190°C). Grease a 12-cup muffin tin or line it with paper liners.
• Step 4: On a lightly floured surface, roll the dough out to a 1/8-inch thickness. Use a 3-inch round cookie cutter to cut out 12 circles for the bases of the pies. Press the dough circles into the prepared muffin cups.
• Step 5: Spoon about 1 tablespoon of mincemeat into each dough-lined cup. Roll out the remaining dough and use a 2-inch round cookie cutter to cut out 12 circles for the tops of the pies. Place the tops over the filled cups, pressing the edges to seal.
• Step 6: Brush the tops of the pies with the egg wash and bake for 20-25 minutes, or until the pastry is golden brown. Allow the pies to cool in the tin for 5 minutes before transferring them to a wire rack to cool completely.
• Step 7: Dust the cooled mince pies with powdered sugar, if desired, and serve.