Preheat the oven to 180C/350F. Line an 8 x 8-inch pan with parchment paper and set aside.
In a large mixing bowl, combine all your ingredients, except for the blueberries and blueberry jam, and mix well.
Make the crumb topping. In a small mixing bowl, combine your dry ingredients and mix well. In a separate small bowl, add your vanilla extract, coconut oil, and maple syrup and whisk together. Combine your wet and dry ingredients and mix very well, until small crumbles remain.
Pour the blueberry crumb bar batter into the lined pan. Firstly, spread the blueberry jam over it, followed by the fresh blueberries. Finally, pour the crumble over the top.
Bake for 20-25 minutes, or until a skewer comes out clean from the center and the crumb topping has become golden brown.
Allow the blueberry bars to cool in the pan completely, before slicing them into 8 bars.
Notes
TO STORE: Place leftover crumb bars in an airtight container in the fridge for up to a week. TO FREEZE: Wrap the bars with food wrap or parchment paper, put them in an airtight bag, and freeze them for up to 6 months. Bring the bars to room temperature before eating them. You can also warm them up in the microwave for 20 to 30 seconds.