1. Combine 3 1/2 cups of the blackberries with the flour and sugar. Spoon the mixture into an unbaked pie shell.

2. Spread the remaining 1/2 cup berries on top of the sweetened berries, then cover with the remaining crust. Pinch edges to seal.

3. Brush the top crust with 2 Tablespoons of milk, and sprinkle with 1/4 cup of sugar.

4. Bake at 425 degrees F for 15 minutes, then turn the oven down to 375 degrees F. Bake for an additional 20 to 25 minutes.