In a large bowl, gently mix together the boysenberries, sugar, all purpose flour and cinnamon. Pour the fruit mixture into a pastry lined pie pan. Cut the butter into small pieces; dot the top of the fruit with the butter.
Top the pie with the second crust; completely seal and flute the edges to make the crust. Make a slight cut with a knife in the middle of the top crust to vent the pie. If you wish to have a shiny/sugary top crust, brush the top crust with a tiny bit of milk (using a pastry brush), then sprinkle with granulated sugar).
For an 8 inch pie, measurements are as follows: 3 cups fresh fruit, 3/4 cup sugar, 1/4 cup flour, 1/4 teaspoon cinnamon, and 1 Tablespoon butter. Same time for baking.
Boysenberry Pie https://www.thegratefulgirlcooks.com/boysenberry-pie/