Preheat oven to 350°F / 180°C and line the bottom of a cake pan with parchment paper.
In a large mixing bowl, mix together all ingredients for the crumble layer until combined.
In another mixing bowl, mix together all ingredients for the raspberry layer, mashing the raspberries with a fork as you go.
Transfer about 2/3 of the crumble mixture to the lined baking pan. Press down firmly with your hands to form the base.
Pour raspberry mixture on top of the base. Spread with a fork or spoon to form an even layer.
Using your hands, crumble the remaining crumble mixture over the top of the raspberry layer.
Bake for 35-40 minutes or until the top is golden brown. Let cool completely before cutting and storing in an airtight container. Enjoy!