Preheat your oven to 180°C (356°F). Gather your ingredients and equipment, including a loaf tin lined with parchment paper.

In a large mixing bowl, beat together the mashed bananas, eggs, and melted butter until smooth.

In a separate bowl, combine almond flour, erythritol, cinnamon, and baking powder. Stir until mixed.

Gradually add the dry mixture to the wet ingredients while mixing gently.

Fold in the crushed walnuts, reserving some to sprinkle on top.

Pour the batter into the prepared loaf tin and sprinkle the reserved walnuts on top.

Bake in the preheated oven for about 40 minutes. Check for doneness at the 30-minute mark.

After 40 minutes, use a toothpick to check the center for doneness.

Let the bread cool in the tin for at least 30 minutes before transferring it to a wire rack.