Preheat oven to 350 degrees Fahrenheit and grease your 9 x 5” loaf pan.
In a large bowl, add the melted butter and bananas. Mash together with a fork until smooth.
Mix in the milk and cinnamon (if using) until well-combined.
Add eggs one at a time, stirring until no yellow streaks remain.
In a separate bowl, stir together flour, sugar, salt, and baking soda.
Add the dry ingredients to the wet ingredients and stir until well combined. Be careful not to overmix the batter so as not to overwork the gluten.
Pour batter and bake for 50 to 55 minutes.
Test doneness with a toothpick; insert one in the center of the loaf. If it comes out clean, it’s ready.
Remove from the oven and let it cool in the plan for a few minutes. Transfer the bread onto a cooling rack to cool completely.