Preheat oven to 375° and spray a 2-3 quart baking dish with a non stick spray. Set aside.
Add cherries to a large mixing bowl.
Sprinkle sugar, brown sugar, lemon juice and corn starch over cherries, gently stir. Let stir for 5 minutes then stir again.
Pour cherries into prepared baking dish. Set aside.
In a medium mixing bowl, whisk flour, sugar, brown sugar, baking powder and salt together.
Using a pastry blender, or a fork, mix butter into flour mixture until crumbly.
Pour boiling water into flour mixture and stir until combined
Spoon mixture over cherries and spread gently making sure to cover the cherries completely.
Sprinkle additional sugar on top of batter.
Bake uncovered for 50 minutes or until topping is cooked thoroughly and has started to brown.
Serve warm topped with vanilla ice cream.