Preheat your oven to 350°F and line a muffin tin with paper liners or grease it lightly.
In a large bowl, combine the mashed sweet potato, mashed avocado, maple syrup, eggs, and vanilla extract. Mix until smooth and well combined.
In another bowl, whisk together the almond flour, cocoa powder, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, stirring until just combined.
If using, fold in the dark chocolate chips.
Divide the batter evenly among the muffin cups, filling each about 2/3 full.
Bake for 20-25 minutes or until a toothpick inserted into the center comes out clean.
Allow the muffins to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.