Perfect Rhubarb Pie

4 cups fresh rhubarb, sliced

4 cups boiling water

1 1/2 cups sugar

3 tablespoons flour

1 teaspoon quick cooking tapioca

1 egg

2 teaspoons cold water

pastry for double crust pie (9")

1 tablespoon butter

Place rhubarb in a colander and pour water over it; set aside.

In a bowl, combine sugar, flour and tapioca; mix well.

Drain rhubarb; add to sugar mixture and toss to coat. Let stand for 15 minutes.

Beat egg and water; add to rhubarb mixture and mix well.

Line a 9-inch pie plate with bottom pastry. Add filling. Dot with butter. Cover with remaining pastry; flute edges. Cut slits in top crust.

Bake at 400ºF for 15 minutes. Reduce heat to 350ºF; bake 40-50 minutes longer or until crust is golden brown and filling is bubbly.