Saskatoon (Serviceberry) Rhubarb Pie

Preheat the oven to 400 degrees F (200 degrees C). Press a pie crust into the bottom and up the sides of each of two 8-inch pie plates.

Combine rhubarb and 1/2 cup of sugar in a microwave-safe bowl. Microwave on high until rhubarb is soft and juice is pooling in the bottom of the bowl, 4 to 5 minutes. Drain juice into a measuring cup and add enough water to make 2 cups. Add cornstarch and stir to dissolve.

Pour 2 cups rhubarb liquid into a saucepan; add remaining 1 cup sugar and lemon juice. Add serviceberries and rhubarb; cook over medium-high heat until thick and bubbling, about 5 minutes. Pour into two pie crusts. Top with remaining crusts and cut holes in the top to vent steam. Pinch the edges together to seal.

Bake in the preheated oven for 15 minutes, then reduce the temperature to 350 degrees F (175 degrees C). Bake until crust is golden brown and filling is bubbling, about 30 more minutes.