Saskatoon Pie - cooking recipe

Ingredients

5 cups saskatoon berries, or as needed
1/4 cup water
1/2 cup white sugar
1 1/2 tablespoons quick-cooking tapioca
2 tablespoons lemon juice
1 tablespoon butter, cut into small pieces (optional)
1 pastry for a 9-inch double crust pie
1 egg white, beaten lightly (optional)
1 tablespoon white sugar

Preparation

Bring saskatoon berries and water to a simmer; cook for 15 minutes. Drain any excess water; set aside to cool to room temperature, about 20 minutes.
Preheat oven to 350 degrees F (175 degrees C).
Whisk 1/2 cup sugar and tapioca together in a bowl. Stir tapioca mixture and lemon juice into berries.
Line a 9-inch pie plate with a single crust; pour berry mixture into crust. Dot berries with butter. Place top crust over berries; crimp edges of pie together tightly. Brush top of pie with egg white.
Bake in the preheated oven for 20 minutes. Remove pie from oven, sprinkle with 1 tablespoon sugar, and return to the oven until pie is golden and filling is bubbly, about 10 minutes.