Preheat your oven to 350°F (175°C).

Grease an 8-inch square baking pan with butter or non-stick spray, or line it with parchment paper.

In a medium mixing bowl, combine the quick or rolled oats, flour, ground cinnamon, salt, baking powder, and sugar. Stir well.

Incorporate melted butter or oil into the dry mixture, mixing thoroughly until the dough resembles coarse crumbs.

Press two-thirds of the dough mixture firmly into the bottom of the prepared pan.

In another bowl, combine the diced strawberries, cornstarch or arrowroot, and maple syrup. Mix well.

Spread the strawberry mixture evenly over the base layer in your pan.

Sprinkle the remaining dough mixture on top, pressing down gently.

Bake for 45 minutes, or until the top is golden brown and the filling is bubbling slightly.

Once baked, remove the pan from the oven and let the bars cool to room temperature for about 15 minutes. Then refrigerate them for at least 30 minutes.