Beat eggs in a large bowl. Pour in soya milk, then gradually whisk in rye flour, cocoa powder, chia seeds, honey, baking powder, and cinnamon. Mix until combined.

Make a double boiler to melt the dark chocolate: take 2 pots, or a pot and a bowl (preferably stainless steel or glass). The bottom of the smaller pot or bowl must not touch the bottom of the larger pot. Pour some water in the larger pot and bring it to a simmer. In the meantime, break the chocolate into pieces. Once the water is boiling, turn the heat down to medium, place the smaller pot or bowl in the larger one and fill it with the pieces of chocolate. Constantly stirring, melt the chocolate and then stir it in with the other ingredients.

Pour the finished batter into preheated waffle maker and bake for 3–4 mins (depending on the type of your waffle maker).