This old-fashioned pie is a Christmas tradition in many families. Look for jars of mincemeat with the pie fillings during the holiday baking season.
Mix all-purpose flour, grated lemon rind and salt in medium-size bowl. Using pastry blender, cut margarine (in small pieces) into flour mixture until coarse crumbs form. Using a fork, gradually stir in ice water until mixture comes together and forms a ball. Shape into disk, about 6 inches in diameter. Divide disk into 2 portions, one-third and two-thirds.
Roll out two-thirds portion of pastry on lightly floured surface into 13-inch circle. Gently fit into 9-inch pie plate. Trim pastry dough to 1/2-inch overhang; cover with damp paper toweling while preparing filling.
Heat oven to 350°F.
Combine apples, mincemeat, cornstarch, lemon rind and juice in large bowl; toss together until well combined. Remove towel from pastry shell; spoon filling into shell, smoothing filling down as much as possible. Dot with butter.
Roll out remaining pastry on lightly floured surface into 12-inch circle. Working about 2-1/2 to 3 inches from edge of circle and using 1-1/2-inch tree-shaped cookie cutter, cut out 8 trees, spacing evenly in a circle over the center of the pastry. Gently roll dough onto rolling pin; unroll dough onto filling, centering over the pie. Trim edge to 1-inch overhang. Fold overhang under the lower crust and make stand-up edge; flute as desired.
Bake in 350°F oven 1 hour and 10 minutes, until crust is golden brown and filling is hot and bubbly (if crust browns too quickly, cover loosely with foil). Remove to rack to cool.