Preheat oven to 350 degrees farenheit.
Use cooking spray to spray the bottom and sides of a 5" x 3" mini loaf pan.
In a medium bowl, mix together almond flour, cinnamon (optional), baking soda, & salt.
In another medium bowl, mix together the melted butter, syrup (or honey), & mashed banana.
Then mix in the egg, lemon juice, and vanilla extract.
Gradually add the dry mixture into the wet mixture and mix well until fully combined.
Spoon batter into loaf pan.
Place loaf pan into oven and bake for approximately 25 to 35 minutes or until a toothpick inserted into the center of the bread comes out clean.