1. Preheat your oven to 350ºF and line a muffin tin with natural nonstick muffin liners.
2. Combine the mashed banana, eggs, tahini, maple syrup, and vanilla in a large bowl. Whisk using a handheld whisk or electric mixer just until the eggs are incorporated.
3. Add in the almond flour, cacao powder, coconut flour, baking soda, and sea salt. Whisk until smooth (there should still be some banana chunks!). Stir in the chocolate chips and walnuts using a rubber spatula.
4. Scoop the batter evenly into the prepared muffin tin. Sprinkle with remaining chocolate chips. Bake muffins for 15 minutes, or until a toothpick inserted into the center comes out clean.
5. Let the muffins cool for about 5 minutes, then enjoy. Store leftovers in an airtight container at room temperature for up to five days.