Preheat the oven

• Preheat the oven to 180 °C (350 °F).

Prepare the strawberry filling

• In a cast iron skillet, stir together the chopped strawberries, white sugar, vanilla extract and flour until the fruit is evenly coated.

Make the crumb topping

• In a mixing bowl, cream together the white sugar, brown sugar and butter.
• Add the cinnamon and flour and stir until smooth.
• Stir in the rolled oats until the mixture is nice and crumbly.

Assemble the crumble

• Spread the crumb topping evenly over the strawberries in the skillet.

Bake

• Bake until the topping is browned and the fruit is bubbling.

Serve

• Let the crumble cool slightly, then serve warm.