In a separate bowl, combine brown sugar and cornstarch. Stir into the strawberry mixture and cook for 2 more minutes until thickened. Remove from heat.

Create the oatmeal crumble by combining all crumble ingredients in a large bowl. Use a pastry cutter or fingers to mix until a coarse crumble forms.

Pour the cheesecake mixture over the baked crust, spreading it evenly. Top with strawberry sauce and then the crumble topping.

Bake the cheesecake bars for 50 to 70 minutes, until the crumble topping is golden brown. Remove from the oven and let cool in the pan on a wire rack for 30 to 60 minutes.

Transfer to the refrigerator and let cool for at least 4 hours, preferably overnight, before slicing into squares.