Mix sugar, cornstarch, water, and vanilla.
Cook over medium heat until thick.
Add berries and pour into baking dish.
For topping, mix flour, sugar, and margarine as if making pie dough.
Add egg. Mixture should appear crumbly.
Sprinkle over fruit mixture.
Bake at 400 degrees for about 40-45 minutes or until topping is lightly browned.