1/2 cup all-purpose flour
1/4 cup white sugar
2 teaspoons baking powder
4 eggs, beaten
2 cups milk, room temperature
1/4 cup lemon juice
1/4 cup orange juice
1 1/2 teaspoons lemon zest
1 cup chopped walnuts
Preheat oven to 350 degrees F (175 degrees C).
In a medium bowl, stir together flour, sugar, baking powder, eggs and milk. Fold in lemon juice and orange juice. Stir in lemon zest and lemon zest. Spread evenly into bottom of pie crust.
Stir together lemon mixture and orange mixture in a small mixing bowl and sprinkle with walnuts. Fill crust with pie filling.
Bake in preheated oven for 50 to 60 minutes, or until custard custard mixture is set and toothpick inserted in center comes out clean. Serve piping hot.