Preheat your oven to 350°F (175°C) to ensure even baking.
Grease your muffin tin with a little butter or line it with muffin liners.
Mash the very ripe bananas in a mixing bowl until smooth, yielding about 1 2/3 cups.
In another bowl, whisk together almond flour, coconut flour, baking powder, baking soda, and salt.
In a large bowl, cream the softened butter and 1/3 cup of brown sugar until light and fluffy.
Add the eggs one at a time, mixing well after each addition, then mix in vanilla extract.
Fold the mashed bananas into the butter and egg mixture until fully combined.
Gradually add the dry ingredients to the wet mixture, folding gently until just combined.
Soften the cream cheese in a small bowl and mix until creamy; add a teaspoon of brown sugar for sweetness if desired.
Spoon a small amount of muffin batter into each muffin cup, add a dollop of cream cheese, then cover with more batter.
Bake for 18-20 minutes, or until a toothpick inserted comes out clean.
Let the muffins cool in the tin for 5 minutes, then transfer to a cooling rack.
