Pre-heat oven to 350 degrees F and allow cold ingredients to reach room temperature. Line a muffin tin with parchment paper liners or lightly grease.
Next coarsely grate your apple with a box grater then chop it into little pieces for apple in every bite! Mash the banana with a fork until smooth.
Add both to a skillet along with coconut oil, sugar, cinnamon, allspice, and nutmeg and saute until tender and fabulously fragrant. Remove from heat, transfer to a large bowl, and allow to cool to room temperature.
While you wait, prep the rest of the recipe. Mince your walnuts until they're super fine (feel free to use a food processor) and combine with remaining streusel ingredients.
Mash and mix the streusel with a fork and/or your fingers until it transforms from powdery to paste-like. The result should be a crumbly, buttery streusel that makes you want to lick your fingers! Make the mixture as sweet or cinnamon-y as you'd like.
Next combine carefully measured flours, baking soda, baking powder, and salt in a medium mixing bowl. Set aside.
Grab your cooled apple-banana mixture and whisk together with yogurt and eggs.
Using a sifter or sieve, slowly sift flour into wet mixture as you mix the two. Stir until just combined. Use a tablespoon to divide batter evenly between 9 muffin cups. (I added a TBSP and a half to each cup) Add a hearty later of streusel on top of each.
Bake at 350 F for 15-18 minutes depending on muffin size. Test with a toothpick in the center around the 15 minute mark and if it comes out clean, pull the muffins; otherwise, test again in a minute or two. Allow to cool and enjoy!
I highly recommend stuffing at least one in your face once they're still hot. So. Much. Yum! Wrap tightly and store on your counter for a few days if needed; 25 seconds in the microwave makes these absolutely divine the next day! Serve them straight up or slathered in apple butter, coconut butter, or even peanut butter.I had to double the streusel topping a few times because my "taste test" turned into me eating it straight from the bowl. Cookie dough fiends will understand; I couldn't help myself!The muffin recipe above is very lightly sweetened and relies on super-ripe bananas. Used to a little more sweet stuff in your muffins? Feel free to add brown sugar, sugar, or preferred sweetener as desired. Nutrition Facts below are estimated using an online recipe nutrition calculator. Adjust as needed and enjoy!