Nepenthe's Triple Berry Pie and the Triple Berry Pie with Tapioca are both good triple berry pie recipes. Nepenthe's pie uses Nepenthe dough and is an excellent summertime recipe.
To make Nepenthe's Triple Berry pie for eight, roll out the dough on a floured board into a 12-inch circle and fit into a 9-inch pie pan. Trim and flute the edges with your thumb. Chill until it's ready to use. Preheat the oven to 350 degrees Fahrenheit. For the filling, mix 3 cups fresh strawberries, 3 cups fresh blackberries, 3 cups fresh raspberries and 2 tablespoons Grand Marnier. Mix 1/2 cup firmly packed brown sugar, 1/4 cup cornstarch, 1 1/2 teaspoons cinnamon in a separate container and add to the berries, tossing gently. Combine and pulse 2/3 cup flour, 2/3 cup whole oats, 2/3 cup packed brown sugar, 2/3 cup walnuts and 1 stick cold butter into a pea-resembling mixture. Put the filling into the pie shell and cover with the topping. Bake for an hour until golden brown.
For the Triple Berry Pie with tapioca, which also serves eight, mix 2 cups of halved strawberries, 1 cup blueberries, 1 cup raspberries, 1 cup sugar and 1/4 cup MINUTE Tapioca. Let the mixture stand for 15 minutes. Preheat oven to 400 degrees Fahrenheit. Prepare 2 ready-to-use refrigerated pie crusts onto to a 9-inch pie plate. Fill with mixture and dot with butter. Cover with the other pie crust and cut slits for steam to escape. Bake for 50 minutes.