Preheat oven to 375° and right before adding crumb mixture, spray a 9 x 13 baking dish with a non stick spray.
Add thawed, sliced strawberries to a medium bowl.
In a small bowl, whisk sugar and corn starch together and sprinkle over strawberries. Gently stir and set aside, stirring occasionally.
In a large bowl, whisk flour, brown sugar, sugar, baking powder, salt and cinnamon together.
Using a pastry blender or a fork, cut butter into flour mixture until crumbly.
In a small bowl, whisk egg and vanilla together and add to flour mixture once butter has been added and mixture is crumbly. Continue using pastry blender until combined.
Remove half of crumb mixture (approximately 3 cups) and press into prepared baking dish.
Stir strawberries and then add to the top of the crumb mixture.
Using clean hands and with the remaining crumb mixture, squeeze with hands to combine and add crumbles over strawberries.
Place in the oven uncovered and bake for approximately 50-55 minutes or until crumb topping is slightly browned.
Let cool completely before cutting into squares.
*If using fresh strawberries, use 4 teaspoons of corn starch.