Preheat oven to 350 degrees. Spray a 13x9 inch casserole dish with non-stick spray.
In a medium bowl, combine strawberries, sugar, lemon juice, and corn starch. Stir well and allow to sit for about 10 minutes while you mix the topping.
Topping:
In a medium bowl, stir flour, sugar, brown sugar, baking powder, and salt well.
Using a fork, mix butter and water into the flour mixture. Stir well. The mixture will be thick.
Pour strawberry filling into the casserole dish. Spread evenly.
With a spoon, drop the flour/sugar mixture over the top of the strawberries. With the back of the spoon, gently spread the topping over the top of the strawberries.
Bake for one hour or until the topping turns brown.
Allow to cool slightly before serving. Top with ice cream if desired.