Ingredients For the Filling 3 cups rhubarb in one-inch pieces, about one pound 2 cups strawberry halves ½ cup sugar 3 tablespoons corn starch or tapioca 3 tablespoons unsalted butter For the Crust 2½ cups all-purpose flour, plus more for dusting ½ teaspoon salt ¾ teaspoon sugar, plus extra for sprinkling 1 5tablespoons unsalted butter (almost 2 sticks), very cold and cut into ¼-inch cubes ½ cup ice-cold water 1 tablespoons milk Instructions Prepare the pastry: combine the flour, salt and sugar in a large mixing bowl.