Preheat oven to 375F and prepare muffin tins by lining with muffin liners.
Add bananas to a medium bowl and mash until there are little to no chunks left.
Add in egg, vanilla extract, melted butter, coconut sugar, maple syrup and sourdough discard. Whisk until ingredients are well incorporated.
In a small bowl, combine flour, salt, baking soda and baking powder. Then, add to wet ingredients and mix until combined.
Add batter to prepared muffin tin and bake for 20-23 minutes or until a toothpick inserted in the center comes out clean.
Let sit for 10 minutes and enjoy warm with a slice of salted butter.
