Pre-heat oven at 165˚C (329˚F).
In a bowl, sift and combine buckwheat flour, almond meal, cacao powder, cornflakes, salt and baking soda.
Combine coconut oil and dark chocolate in a pyrex jug and stand in a saucepan filled with boiling water. Stir until melted, then add coconut sugar, coconut milk and vanilla, continue to heat until smooth, then pour over the dry mixture and use a spatula to combine.
Shape the mixture into rounds, about 1 tablespoon per, and space evenly on a tray lined with baking paper.
Place on a rack in the middle of your oven and bake for up to 12 minutes. Remove and let cool entirely before icing.
Combine all ingredients in a pyrex jug and stand in a saucepan filled with boiling water. Stir vigorously to melt and combine, the texture should be thick.
Remove from the heat then use a teaspoon per mixture to ice the biscuits. Top with half a walnut. Enjoy!