In a large mixing bowl, whisk together cocoa powder, coconut flour, baking soda and salt.
Add in honey and melted coconut oil and whisk till combined. Batter will be very thick.
Whisk eggs in one at a time, making sure each egg is fully combined before adding the next one in.
Set batter aside and chop up chocolate bar and walnuts.
Add chocolate chunks and chopped walnut to batter and mix well.
Line a muffin pan with liners and divide batter evenly between all 12.
Bake muffins at 350 for 20 minutes.
Let cool in pan for 5 minutes and then transfer to wire rack to finish cooling.