Heat your oven to 350 degrees. Then in an electric mixer, cream the butter and brown sugar together. Then add the bananas and mix until smooth.
Next add the almond meal. Once fully incorporated add the eggs and gluten free flour. Then add the walnuts, baking soda, nutmeg, salt and vanilla. Mix to incorporate.
Pour the batter into a bread pan, and bake for 45-55 minutes. You want the bread to be golden brown, and you want a toothpick inserted into the center of the bread to come out clean.