In a food processor or bowl, combine 3/4 cup pastry flour and 1/4 teaspoon salt. Cut cold butter in to flour until pieces are slightly larger than pea size. Mix in 2 tablespoons water and continue to add a bit of water until dough comes together. Place in refrigerator.
Preheat oven to 375˚.
In a separate bowl combine blackberries, maple syrup, 2 tablespoons pastry flour, and 1 teaspoon cardamom. Stir until blackberries are coated.
Once oven is ready, remove dough from refrigerator. On a floured surface, roll dough out to a 12" circle. Transfer to a baking sheet. Place blackberry filling in center, leaving roughly a 2" border. Fold outside edges over dough.
Bake for 45-55 minutes or until crust is golden brown and berries are soft. Serve with yogurt or ice cream.