Stir the cocoa, baking soda, salt, and cinnamon in a small bowl.
Whisk the eggs with the melted butter, sugar, and vanilla In a separate bowl.
Add the cocoa mixture and stir well;
Add this cocoa/egg mixture to your sourdough levain mixture all at once.
Stir thoroughly - you don't want streaks of unmixed sourdough in your batter. The batter will start to swell from the baking soda acting with the kefir and sourdough.
Stir in the chocolate chips.
Pre-heat your waffle iron and cook according to your manufacturer's instructions. My waffles take about 3 to 5 minutes.
The waffles will feel soft coming out of the waffle iron but will crisp up again when you remove them.