First make the crust. In the bowl of a food processor, combine the flour and salt.
Drop in the cold butter chunks and pulse until the mixture resembles coarse almond meal. Add the cold water and pulse until the mixture forms a dough.
Divide the dough into two, pat into disks and wrap in plastic. Refrigerate for 45 minutes.
Preheat the oven to 400 ºF (200 °C).
Roll one disk of dough at a time fairly thin. Cut out 3.5" circles and small snowflakes. You will use all the dough to cut out 22 circles and 22 snowflakes. Make sure to re-roll scraps.
Fit the circles into the wells of regular size muffin tins. Fill each tart shell with 1-½ tablespoon (22 mL) of mincemeat filing per tart. Top each with a snowflake.
Bake until they begin to brown and the filling is bubbling (20–25 minutes). Let cool slightly before carefully un-moulding.