Preheat the oven to 350 degrees F. Line a 9-inch × 9-inch baking pan with parchment paper and set aside.

Combine graham cracker crumbs and sugar in a medium bowl and stir together. Pour the melted butter into the bowl and mix until evenly combined.

Transfer the crust mixture to the prepared baking pan and gently press the mixture into the bottom of the pan in an even layer. Bake for 8 minutes.

While the crust is baking, beat together the cheesecake ingredients in a medium bowl until smooth and creamy. Set aside.

Add the strawberries and lemon juice to a medium saucepan. Cook over medium-high heat for 5 to 7 minutes until the strawberries burst and juice starts to form.

In a separate bowl, combine the brown sugar and cornstarch. Then stir it into the strawberry mixture and cook for an additional 2 minutes, stirring constantly. Once the mixture has thickened and resembles pie filling, remove from heat. Set aside.

Make the oatmeal crumble by combining the oats, brown sugar, cinnamon, and salt in a large bowl. Use a pastry cutter or a fork to cut the butter into the mixture until it resembles tiny pebbles.

To assemble, pour the cheesecake mixture over the baked crust and spread into an even layer. Top with the strawberry sauce, spreading it out carefully. Sprinkle the oatmeal crumble over the top.

Bake for 50 to 70 minutes, until the top of the crumble is golden brown.

Remove from the oven and let cool in the pan on a wire rack for 30 to 60 minutes. Then transfer the bars to the refrigerator to cool for at least 4 hours, preferably overnight, before slicing into squares.