Wash, drain and pat dry beans if using canned ones to avoid the bean-y taste.
Put them in food processor with melted coconut oil, agave syrup, salt and vanilla and blend until smooth and creamy.
Place in a bowl ground hazelnuts, cocoa, rice flour, xantan gum, instant coffee, baking soda and baking powder. Mix carefully and add milk with apple cider vinegar.
Now add blended mixture of beans to it and mix carefully. Keep mixing and adding milk gradually.
The consistency should be fairly thick but still pourable. At this point you can fold in chocolate chips if using.
Pour it in a lined tin 20x20 cm and sprinkle chopped hazelnuts on top (or chocolate if you prefer).
Bake on 180° for 30 minutes.
Test if it's done with a tooth pick. It should come out clean. They will still be pretty soft when ready.
Leave them to cool as they will firm up.
Keep in the fridge to get them to be even firmer