In a medium pot, combine sugar, cornstarch, and water. Mix until smooth.
Stir in orange juice, zest, lemon juice, and raisins. Cook over medium heat until bubbling and thick. Cook 1 more minute.
Remove from heat, stir in walnuts, and cool completely.
Line a 9-inch pie plate with one crust. Fill with cooled raisin mixture. Top with second crust and seal the edges. Cut vents in the top.
Brush with egg white and sprinkle with sugar.
Bake at 400°F for 35–40 minutes, shielding with foil if needed.
Cool for at least 1 hour before serving.