Perfect Rhubarb Pie

Ingredients

• 1) Sliced fresh or frozen rhubarb – 2 cups. (Thawed)
• 2) Boiling water - 4 cups.
• 3) Sugar – 1 1/2 cups.
• 4) All purpose flour - 3 tablespoons.
• 5) Fast cooking tapioca - 1 teaspoon.
• 6) Large egg – 1no.
• 7) Cold water - 2 teaspoons.
• 8) Pastry - For double-crust pie and it should be 9 inches.
• 9) Butter - 1 tablespoon.