Preheat the oven to 350°F/180°C and line a loaf pan or cake pan with baking paper.
In a large mixing bowl, mash the banana with the back of a fork. Whisk in the melted butter, eggs, and vanilla and combine.
Add the almond flour, flax meal, Erythritol, baking powder, and salt. Fold in with a spatula to make a batter.
Pour the batter into the loaf pan and bake in the oven for 30 minutes until golden brown.
Allow it to reach room temperature. Remove from the tin, slice, and serve.