01 - Preheat the oven to 350°F. Line an 8-inch square baking pan with parchment paper, leaving an overhang on two sides for easy removal.
02 - In a large bowl, combine the flour, oats, brown sugar, cinnamon, and salt. Pour in the melted butter and stir until the mixture resembles coarse crumbs and everything is evenly moistened.
03 - Reserve about 3/4 cup of the crumble mixture for the topping. Press the remaining mixture firmly and evenly into the bottom of the prepared pan to create a solid crust layer.
04 - In a separate bowl, combine the chopped strawberries, granulated sugar, cornstarch, and lemon juice. Mix gently until the strawberries are evenly coated with the sugar mixture.
05 - Spread the strawberry mixture evenly over the prepared crust. Sprinkle the reserved crumble mixture over the strawberries in an even layer.
06 - Bake for 35 to 38 minutes, or until the topping is golden brown and the strawberry filling is bubbling around the edges.
07 - Let the bars cool completely in the pan on a wire rack. Once fully cooled, use the parchment paper overhang to lift the bars out of the pan, then cut into 16 squares.