Here's a recipe using tapioca that I had. Haven't used it for years, but I think it turned out pretty good. I'm going to try it for DH's BD next week.
Strawberry Rhubarb Pie
Ingredients:
1 1/2 pt Fresh strawberries; halved
2 c Sliced fresh rhubarb (2 to 3 medium stalks)
1 1/2 c Sugar
6 T Quick-cooking tapioca
Unbaked pastry for double-crust 9-inch pie
Milk as needed
Sugar as needed
Flour as needed
Procedure:
Mix strawberries and rhubarb with 1 1/2 cups sugar and the tapioca; let stand while making pastry. Divide pastry in half. On lightly floured surface roll out one portion 1 1/2 inches larger than inverted 9-inch pie plate. Fit into plate and trim crust even with edge. Fill with fruit mixture. Roll out remaining pastry; lift onto pie. Trim crust 1/2 inch beyond edge of pie plate.
Fold top crust under bottom crust; seal together to make a standing rim and flute edge. Cut vents in top crust. Brush with milk and sprinkle with sugar. Bake in 400 F. oven 60 to 70 minutes, or until filling bubbles in the center. After 30 minutes of baking, check pie occasionally and cover edges with foil, if necessary, to prevent browning. If pie begins to boil over, place foil beneath pie plate. Cool thoroughly before cutting. Makes one 9-inch pie.