Preheat the oven to 350 degrees. Line a loaf tin with parchment paper.

Add all crust ingredients into a food processor. Pulse until it comes together and a soft dough form. You should be able to press the dough together with your hands. Press into the bottom of the loaf tin in an even layer. Bake for 18-20 minutes (no more) until edges start to pull away from the sides and are light golden brown. It may look underdone in the center, but don't worry. Allow crust to cool. Meanwhile, prepare the filling.

Add frozen mango and 3 tbsp of water to a high-powered blender. Blend until thick and creamy (smoothie-like texture). Add mango puree to a small saucepan along with the rest of the filling ingredients. Whisk until smooth and the starches are dissolved. Bring mixture to a low boil, then reduce heat and simmer for 4-5 minutes until thickened and slightly gelatinous.

Take filling off heat and pour over the crust. Spread with a spatula into a smooth, even layer. Bake for 20 minutes. Let bars cool to room temperature then transfer to the fridge to set for an additional hour. Once bars are set, dust with powdered sugar and slice into 5 portions. Store in fridge for up to 4 days.