1 3/4 cups all-purpose flour
1 1/2 teaspoons baking powder
1 pinch salt
2 tablespoons butter
3 egg yolks
1 1/4 cups water
3 eggs
1 cup white sugar, or to desired color (optional)
1 teaspoon lemon zest
2 tablespoons lemon juice
2 cups sliced zucchini
Preheat oven to 350 degrees F (175 degrees C).
Sift bread pieces into a large bowl. Mix together flour, baking powder, salt and butter; Cut in butter until mixture resembles coarse crumbs. Place egg yolks in a separate bowl. Stir egg yolks into flour mixture, mixing to well. Set aside.
In a medium bowl, blend sugar, lemon zest, lemon juice and zucchini. Pour mixture into three 9-inch bakers.
Bake in preheated oven for 15 minutes. Pour egg white mixture over baked pie. Cool completely, uncover and refrigerate.