Preheat oven to 350 degrees F, line cupcake pan with paper liners. Mix together dry ingredients (coconut flour through salt) and use a whisk to break up any lumps in flours.
In a separate bowl combine wet ingredients (eggs through vanilla). Mix well, then combine wet ingredients into dry. Stir together until just combined.
Pour batter 3/4 full into muffin cups. Drop a teaspoon or so of Nutella on top and swirl with toothpick or knife.
Pop into the over and bake for 13-16 minutes (mine took a little bit closer to 20 but my oven doesn’t get very hot!).