1 cup dairy-free dark chocolate chips (such as Enjoy Life brand or raw cacao nibs)
Preheat oven to 350 degrees. Line 10 muffin cups with paper liners.
Combine 1/2 cup of the maple syrup, walnut butter, 1/2 cup of the cacao powder, 1/4 teaspoon vanilla extract and pinch of sea salt in a mixing bowl and whisk until ingredients are super smooth. Set chocolate-walnut spread aside.
In a large bowl, mix together the flour, remaining 1/3 cup cacao powder, chia seeds, baking soda, and 3/4 teaspoon sea salt.
In a separate bowl, mix together the remaining 1 cup of maple syrup, banana, water, coconut milk, lemon juice and remaining 1/4 teaspoon vanilla extract. Fold the wet ingredients in with the dry.
Beat egg whites to stiff peaks. Carefully fold the egg whites into the batter. Fold in the cacao nibs (or chocolate chips.) Bake for 18 to 20 minutes, or until a toothpick inserted in the middle comes clean. Set on a wire rack to cool. Serve with chocolate-walnut spread.
Chocolate-Walnut Spread can be made up to 4 days in advance and stored in a covered container in the fridge. Chocolate Chip Muffins can be stored in a zip-top bag in the freezer for up to 3 weeks.