Preheat your oven to 150°C (305°F) on fan bake and grease a 24cm (9 inch) cake tin with coconut oil.
Put dates in a blender and pour over boiling water to soak.
Mix all crumble ingredients in a bowl, then pour in coconut oil, stirring with a knife to create a crumbly mixture.
Sift dry ingredients into another bowl.
Add remaining wet ingredients except feijoas to the blender and process until smooth, then pour into the dry mix.
Lift and fold the mixture until almost combined, then add the feijoas and stir through - you want a few flour flecks to remain.
Dollops large spoonfuls of the mixture into your tin and spread gently to the edges, then sprinkle over the crumble mixture.
Bake for 45-50 minutes until a skewer comes out relatively dry in the middle.
Remove and let cool, then remove from the tin and slice.