Preheat the oven to 375°F (190°C).
In a large mixing bowl, combine strawberries, granulated sugar, cornstarch, lemon juice, and vanilla extract until berries are evenly coated.
Transfer the strawberry mixture to a 9x9 inch (23x23 cm) baking dish and spread into an even layer.
In a separate medium bowl, whisk together flour, oats, brown sugar, salt, and cinnamon.
Add cold cubed butter to the dry mixture and use a pastry cutter or fingertips to incorporate until it forms pea-sized crumbs.
Sprinkle the crumble mixture evenly over the strawberry base.
Bake for 35 to 40 minutes, or until the fruit juices are bubbling and the topping is golden brown.
Remove from oven and allow to cool for at least 15 minutes to let the filling set before serving.