Preheat your oven to 350Β°F (175Β°C). Grease a standard loaf pan with butter and set aside. In the meantime, mash up two ripe bananas in a large bowl until they are almost liquid.
In another mixing bowl combine gluten-free all-purpose flour, baking soda, cinnamon, and salt to make dry ingredients for mixture. Mix sugar with the butter till it becomes lightly crumbly texture resembling sand (itβs called creaming method). Add eggs one by one into this wet mix followed by vanilla extract.
Slowly fold in mashed bananas and then dry ingredients until they are just combined. Pour the batter immediately onto your prepared loaf pan, spreading evenly with a spatula or wooden mixing stick to about 1/2-inch from edges of container (this will help it rise uniformly).
Bake for approximately 50 minutes - check at around this time if you have an oven that tends towards overcooking. The bread is done when the top has turned golden brown and a tester inserted into center comes out clean.
Remove from heat, cool on wire rack to room temperature (this helps it firm up).