Preheat the oven to 350°F.

Lightly oil an 9x5-inch loaf pan with a small amount of margarine.

Combine quinoa flakes, bean flour, potato starch, tapioca flour, baking powder, salt and xanthan gum in a large bowl.

Mix together with a whisk and set aside. Whisk together mashed bananas, eggs and margarine together in a separate bowl.

Add sugar, cranberries and lemon juice; mix until blended.

Gently stir the banana mixture into the flour mixture until just combined. Do not over mix the batter.

Pour batter into the prepared loaf pan and bake until lightly browned, about 40 minutes.

Allow the bread to cool completely in the pan, about 1 hour.

Turn the bread out onto a cutting board and, using a serrated bread knife, slice the bread into 3/4-inch thick pieces.

Arrange on a platter and serve.