Preheat oven to 350 degrees F (175 degrees C). Line a loaf pan with parchment paper.
Mash bananas in a large bowl. Add egg; beat until combined. Mix in flour, honey, oil, flaxseed meal, vanilla extract, baking powder, baking soda, xanthan gum, nutmeg, and salt. Fold in pecans. Pour batter into the lined loaf pan.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, 50 to 60 minutes.