How to Make It
Preheat oven to 350° and line muffin pans with muffin liners. Drain the dates and place in a blender or food processor with 1/4 cup clean water and process until a thick paste has formed. Set aside.
In a large bowl, whisk together the flours, baking soda, salt and spices. Make a well in the center of the dry ingredients and add date paste, yogurt, egg, banana, coconut oil and vanilla. Whisk together and then slowly start folding the dry ingredients into the center until a wet dough forms. Fold in the mango chunks and coconut.
Divide the dough evenly between the muffin pans. Make the streusel by combining all the ingredients in a bowl and use fingers to incorporate the butter into the mixture. Sprinkle a little on each muffin and stick in the oven for 7 to 10 minutes (12 to 15 minutes for regular-size muffins) or until they are puffed and the streusel has just started to brown.
Remove from oven and enjoy warm on their own or with jam for a sweeter treat.