Preheat oven to 350 F.
Blend ricotta, sugar, and egg yolks in lg bowl. Beat egg whites and blend in to ricotta mixture. Add milk, wheat, candied peels, cinnamon, and orange water. Blend thoroughly.
Divide pasta frolla in slightly unequal portions. On lightly floured board, roll out lg portion from center, keeping in circular shape, until dough is approx. 1/8" thick. Transfer to 9½" deep-dish pie plate. Fill pie plate w/ ricotta mixture. Roll out remaining pasta frolla. Cut into 1/2"-3/4" strips. Make criss-cross top. Crimp edges together and trim off extra dough.
Bake at 350 F until filling is firm and golden, approx. 90 min. Remove from oven. Let cool. Dust w/ powdered sugar as desired before serving. Pie should keep 3-4 days in fridge.