Preheat oven to 350F
For the filling: Place the first four filling ingredients in a heavy-bottomed pot. Set the heat to medium and allow the berries to thaw gradually. Bring the mixture to a simmer and cook until it reduces a little and begins to naturally thicken (about 30 minutes or so). Mix together cornstarch and water. Add it to the berry mixture and stir constantly over medium-high heat until it comes to a boil. Boil for about 30 seconds to ensure there's no starchy taste left. Remove from heat and set aside.
For the crumble: Thoroughly combine all dry ingredients. Cut in the butter until it resembles coarse cornmeal.
Coat a 9"x13" pan with cooking spray and pour the berry mixture in (remove the star anise). Top with the crumble mixture. (Alternatively, you may put down half the crumble mixture as a base and the other half as a topping - both are delicious.) Bake for 30-45 minutes. The mixture should be bubbling and the topping golden and starting to crisp. If not, continue baking another 10 minutes and check again - ovens vary. Cool completely and cut, or scoop, while warm and serve topped with vanilla ice cream. Yield: 12 servings.