Rhubarb Orange Meringue Pie

Name: Rhubarb Orange Meringue Pie
Ingredients: 1 frozen pie crust (see pie crust recipe for instructions to make your own); 3 1/2 to 4 cups chopped rhubarb stalks (about 1 lb); 3/4 cup white granulated sugar; 1 Tbsp orange zest; 1/4 teaspoon cinnamon; 1/4 teaspoon ground ginger; 3 Tbsp instant tapioca or 2 Tbsp tapioca flour/starch (can sub 2 Tbsp corn starch); 1 Tbsp corn starch; 1/3 cup cold water; 1/4 teaspoon cream of tartar (can use vinegar instead of cream of tartar, see method instructions); 1/2 cup white granulated sugar; 4 large egg whites (room temperature); 1/2 teaspoon vanilla extract