Step 1: Preheat your oven to 350°F (175°C).
Step 2: Line your muffin tin with parchment paper liners or grease them lightly with ghee.
Step 3: In a large mixing bowl, whisk together the almond flour, coconut flour, baking powder, baking soda, salt, and monk fruit until well combined.
Step 4: In another bowl, beat the eggs, then add in the melted ghee, coconut milk, and vanilla extract. Mix until fully incorporated.
Step 5: Pour the wet mixture into the dry ingredients and stir until just combined.
Step 6: Gently fold in the Stevia-sweetened chocolate chips and diced black walnuts.
Step 7: Spoon the batter into the prepared muffin tin, filling each cup about three-quarters full.
Step 8: Place the muffin tin in the preheated oven and bake for 20-25 minutes.
Step 9: Once baked, let the muffins cool in the tin for about 5 minutes before transferring them to a wire rack.