Preheat oven to 450°F.
Divide pastry into 2 portions.
Roll out 1 portion between 2 sheets of wax paper into a 9 X 9-inch square.
Remove top piece of wax paper.
Cut dough into 3-inch squares.
Fit each square into a 2 1/2-inch fluted tart pan.
Press edges to remove any overhang.
Prick dough with a fork on bottom and sides.
Repeat until all dough has been used, rerolling scraps.
If you don't have 18 tart pans, you can make tarts in batches, reusing pans.
Place tarts on a large baking sheet on top shelf of oven.
Reduce heat to 400° F.
Bake for 15 minutes, or until lightly browned.
Cool tarts on wire racks until they can be handled comfortably.
Invert on palm of hand and gently tap on bottom to remove from pans.
Finish cooling on wire racks.
In a medium-size bowl, mix together mincemeat and mashed Cranberry Jelly.
Bring to room temperature.