Preheat the oven to 350 degrees Fahrenheit and line an 8” x 8” baking dish with parchment paper.

Add all of the ingredients for the crust and topping to a large bowl and stir well until everything is combined. The dough should be somewhat crumbly and not over oily. 

Measure out ½ cup of the mixture and set it aside to reserve as the crumble topping. Transfer the remaining crust mixture to the parchment-lined prepared pan and press it into an even layer.

Use a fork to poke several holes into the crust.

Bake the crust for 15 to 20 minutes, or until it is just slightly golden brown.

While the crust is baking, prepare the strawberry mixture. To do so, transfer the strawberries and granulated sugar (or pure maple syrup) to a saucepan with 2 tablespoons of water. Cover the pan and heat it on the stove top over medium heat.

Allow the mixture to come to a full boil and cook until the strawberries are very soft and much liquid is seeping out, about 8 to 10 minutes. Mash the strawberries using a spoon or fork until they reach your desired texture. Stir in the gluten-free all-purpose flour (or tapioca flour or corn starch) and continue cooking without the lid until the strawberry filling is nice and thick, about another 2 to 3 minutes.

Once the crust is out of the oven, pour the strawberry filling mixture over it and spread it evenly. Sprinkle the reserved crumble mixture on top.

Bake for 22 to 30 minutes, or until the topping is golden-brown.

Remove the strawberry oatmeal bars from the oven and allow them to cool completely before slicing and serving.

Serve with a scoop of vanilla ice cream and fresh berries for an even more decadent dessert.