Sweet, tart blackberries in sugary pie crust baked up warm and gooey.

Stir together first four ingredients in a large bowl. Gently stir in blackberries until sugar mixture is crumbly. Spoon fruit mixture into a lightly greased 11 x 7 - inch baking dish. Cut piecrust into 1/2 - inch wide strips, and arrange strips diagonally over blackberry mixture. Sprinkle top with 1 tablespoon sugar.

Bake at 425 degrees F for 45 minutes or until crust is golden brown and center is bubbly. Serve with ice cream if desired.