Preheat the Oven: Begin by preheating your oven to 350°F (175°C).
Prepare the Strawberries: In a mixing bowl, combine the sliced strawberries with granulated sugar, cornstarch, and lemon juice. Toss to coat everything evenly, then pour this mixture into a baking dish.
Make the Crumble: In another bowl, mix together the flour, oats, brown sugar, cinnamon, and salt. Cut in the softened butter until the mixture resembles coarse crumbs.
Assemble the Dish: Sprinkle the crumble mixture evenly over the strawberries in the baking dish.
Bake: Place the dish in the oven and bake for 30-35 minutes, or until the topping is golden brown and the strawberries are bubbling.
Serve: Let it cool slightly before serving warm or at room temperature.