Ingredients:

• 3 1/2 cups (440g) rhubarb stalks cut into 1/2 inch pieces (trim away and discard the leaves which are poisonous; trim ends)
• 2 cups (280g) stemmed and sliced strawberries
• 3/4 to 1 cup sugar (depending on how tart/sweet you like your pie)
• 4 tablespoons quick cooking ("minute") tapioca
• 1/4 teaspoon salt
• 1 teaspoon finely grated orange zest
• 1 double-crust 9-inch pie dough recipe, like this one or your favorite pie crust recipe
• 1 large egg white, beaten, or 1 tablespoon cream for brushing, optional