Combine in bowl: eggs, yogurt, fat of choice, maple syrup, and vanilla.
In separate bowl sift together cassava flour, cocoa powder, collagen, baking soda, and sea salt. Add shaved chocolate.
Add dry ingredients to wet ingredients and use spatula to mix together thoroughly, without over-mixing.
Fill lined muffin pan with batter. Place muffin pan in room temperature oven overnight (or for 4 hours) to ferment. (Muffins may also be baked immediately, if you don't wish to ferment the batter.)