Creating Strawberry Oatmeal Crumble Bars is a straightforward process if you follow these steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C) and line a 9×13-inch baking dish with parchment paper.
2. Mix Oats and Flour: In a large bowl, combine the rolled oats, all-purpose flour, brown sugar, granulated sugar, cinnamon, and salt.
3. Add Butter: Pour the melted butter into the oat mixture and stir until well combined. It should resemble a crumbly texture.
4. Prepare Strawberries: In another bowl, toss the sliced strawberries with lemon juice and cornstarch. Ensure that the strawberries get well coated.
5. Layer the Mixture: Press half of the oat mixture into the bottom of the prepared baking dish, creating an even layer.
6. Add Strawberries: Spoon the strawberry mixture over the oat layer, spreading it out evenly.
7. Top with Crumble: Sprinkle the remaining oat mixture over the strawberry layer, covering it evenly.
8. Bake: Place the dish in the preheated oven and bake for 35-40 minutes, or until the top is golden brown and the strawberries are bubbling.
9. Cool: Remove from the oven and let cool in the baking dish for about 10-15 minutes. Then, lift the bars out using the parchment paper and allow them to cool completely on a wire rack.
10. Slice and Serve: Once cooled, slice into squares and enjoy!

These steps will guide you towards creating delicious Strawberry Oatmeal Crumble Bars that will leave everyone wanting more.