Blackberry cobbler

1. Stir together first 4 ingredients; let mixture stand 10 minutes or until sugar dissolved.
Roll half of pastry to 1/4 -inch wide strips. Place in 9 x 13 inch baking dish. Bake at 425 for 10 minutes or until lightly browned. Spoon blackberry mixture on top of pastry. Dot with butter. Roll remaining pastry and cut into strips. Arrange on top of blackberry mixture. Sprinkle with sugar. Bake at 400 for 30 minutes. Serve with vanilla ice cream , if desired.