Preheat oven to 350 degrees F. Grease muffin tin or line with 10 silicone baking cups.
In a large bowl, add the almond flour, coconut flour, baking soda, salt, cinnamon and nutmeg. Mix together, making sure to break up any chunks. Add the eggs, coconut oil, maple syrup, crushed pineapple, and carrot. Mix until evenly incorporated. The batter will be pretty thick.
Evenly distribute the mixture among 10 muffin cups or silicone cups. Use a spatula to smooth the surface.
Bake for 17-20 minutes or until inserted toothpick comes out clean. Allow to cool.
Meanwhile, add the cream cheese, maple syrup and vanilla to a small bowl and mix together until smooth and creamy.
Using a knife, smooth frosting over the top of each muffin. Top with a sprinkle of chopped walnuts, if desired.
Bake for 17-20 minutes or until inserted toothpick comes out clean.