Mix flax seeds with water and let them soak for 10 minutes.
In a large bowl mix all the dry ingredients (flour, hazelnut meal, baking powder, coconut sugar, cocoa powder).
In another bowl mix the wet ingredients (date syrup, plant based milk, coconut oil, rum and pre-soaked flax seeds).
Add wet ingredients to the dry ingredients and mix well with a hand mixer.
Add chocolate chips and mix them gently into the batter.
Pour batter into 18 muffin tins and bake for 20 minutes in a preheated oven at 180°C.
Once they are baked, let them cool down on a cooling rack, so they don't crumble.