Berry Rhubarb Pie

 cup all-purpose flour

 cup butter

 pinches salt

 cups fresh chopped rhubarb

 cups berries of your choice, chopped to similar sizes

 cups brown sugar

 tablespoons preferred baking starch (cornstarch, tapioca starch, etc.)

 teaspoons mixed lemon juice and zest

 teaspoon cinnamon

 teaspoon allspice

 teaspoon vanilla extract

 egg