Preheat the oven to 350°F (175°C). Prepare a 12-cup muffin tin by greasing or lining with paper liners.

Mix the dry ingredients: In a medium bowl, sift together the flour, oats, Splenda, baking powder, baking soda, cornstarch, cinnamon, nutmeg (if using), and salt. Set aside.

Mash and mix: Mash the bananas in a large bowl until chunky. In a separate bowl, whisk the eggs, melted margarine, vanilla extract, and almond extract (if using).

Combine wet and dry: Add the egg mixture to the mashed bananas and mix until combined but still slightly chunky.

Add mix-ins: Fold in the dark chocolate morsels and crushed walnuts.

Incorporate dry ingredients: Gradually fold the dry mixture into the wet mixture in three parts, ensuring it's evenly combined. Let the batter rest for 5 minutes.

Fill and bake: Spoon the batter evenly into the prepared muffin cups. Bake for 25-30 minutes, or until the tops spring back when lightly pressed.

Cool and enjoy: Allow the muffins to cool in the tin for a few minutes, then transfer them to a wire rack to cool completely.

Tips for Success: For extra moisture, you may need to add 1/8 to 1/4 cup water depending on the ripeness and size of the bananas. Sprinkle additional chocolate morsels and crushed walnuts on top of the muffins before baking for a bakery-style finish. These muffins have a sponge-like texture, perfect for pairing with coffee or tea