Preheat oven to 365 F.
Use two sheets semi-thawed pastry to line fluted tart pan approximately 10 inches, pressing and trimming neatly to fit; chill 15 minutes.
Peel, core and thinly slice apples into large bowl; sprinkle with sugar, lemon zest and cornstarch then toss well to evenly coat.
Arrange apple slices in pastry-lined tart pan, laying flat.
Beat egg with milk. Brush egg wash around pastry rim.
Cut 1/2-inch strips from remaining pastry sheet and make lattice pattern over apples, crimping edges once lattice is completed.
Brush tart with egg wash and sprinkle with cinnamon sugar.
Bake 35-40 minutes, or until pastry is golden. Allow to cool at least 15 minutes before slicing. Serve with ice cream, custard or cream, if desired.