Preheat oven to 375 degrees F. Place the butter, sugar, flour and cinnamon in a bowl. With a pastry cutter, your fingers or two forks, work until well blended, then set aside. Make the batter by beating the oil, sugar and egg until well-combined. Beat in buttermilk. Add the flour, baking powder and salt and mix until just combined. Gently fold in the berries. Spoon the batter into a lightly, greased 8-inch baking dish. Sprinkle on the topping. Bake 45 minutes, or until a toothpick inserted in centre comes out clean.