Crust

Food Processor

• Add flour, sugar, and salt to the food processor. Pulse until mixed. Open the lid and scatter the butter over the dry ingredients. Pulse about 7-8 times. Open and drizzle 3/4 of the water/vinegar over the mixture and cover. Pulse again until the mixture resembles coarse crumbs, about 5-6 times. Avoid the dough balling around the blades. Squeeze the dough between your fingers. If the dough seems dry, slowly add more water and pulse 1-2 more times. Depending on season and outside temperature, you may or may not use all of the water.  
• Carefully pour mixture onto your work surface. Ball the dough, then flatten into a 3/4-inch disk and wrap. Refrigerate for at least an hour or overnight.

By Hand

• Combine flour, sugar, and salt in a large bowl. Add the butter and coat with the dry mixture. With a pastry blender cut in the butter. Drizzle the water in three stages, if needed. Distribute the water until dough forms.

Pie

• On a lightly floured surface, roll dough into a 12-inch circle. Transfer the dough to a 9-inch pie pan. Let the pastry fall into the pan. Trim the edges to 1/2-inch beyond the pie pan. Tuck the overhang under itself and flute the crust. Crack and separate an egg white. Brush the bottom and midway up the side to seal the crust and prevent a soggy bottom. Place in the refrigerator until ready to fill. 
• In a large bowl, blackberries, 3/4 cup sugar, orange juice, zest, and vanilla extract. Mix gently several times and set aside for 10 minutes.

  Preheat oven:

  400°F (at high altitude)

  375°F (at sea level)
• In a small bowl, combine the remaining 2 tablespoons sugar, cornstarch, cinnamon, nutmeg, and fresh mint. Mix, then to enhance the flavor of the mint, rub the sugar against the leaves with your fingers. Add cornstarch mixture to the fruit and combine until no more white is seen.
• Take the shell from the refrigerator and pour the fruit mixture into the pie. Make sure to spatula the sides of the bowl, as this is where precious juices and thickening agents like to hide.
• Place pie plate in the refrigerator or freezer until the fluted piecrust is hard to the touch. 
• Place pie on the center rack and bake for 30 minutes.
• High Altitude Only - reduce temperature from 400° to 375° after 15 minutes.
• Meanwhile, make the streusel topping. Combine the flour(s), sucanat, sugar, and cinnamon in a medium-sized bowl, then add the butter. Coat the butter with the flour mixture. Using two knives or a pastry cutter, push the butter into the dry ingredients until the mixture resembles a small/medium crumb. Gradually mix in the oats. Refrigerate until ready for use.
• After 30 minutes total, remove pie from oven and add streusel to the top. Turn the oven down to 375°, place a pie shield around edges to prevent over browning, slide a pan one rack below, and rotate the pie 180°. Continue baking for another 30-35 minutes, or until the top is golden and the juices are slow to bubble. 
• Once pie has finished baking, transfer to a wire rack. Let cool for at least three hours or overnight. Slice and enjoy!