Preheat the oven to 350ºF. Grease your loaf pan.
In a large bowl, mash the bananas in a bowl until they are mostly smooth. Add the melted butter and mix.
Add the baking soda, salt, and egg. Mix, making sure to break the yolk.
Add the white sugar, vanilla, and cinnamon (optional). Add the flour and combine until no lumps of flour are left.
Here is where you would add optional add-ins, like blueberries or chocolate chips.
In the greased loaf pan, sprinkle half the brown sugar.
Add the batter, then sprinkle over the remaining brown sugar.
For an 8"x4" loaf pan, bake for 50-60 minutes. For an 9"x5" loaf pan, bake for 45-50 minutes. Bake until a toothpick inserted comes out clean.
Let it cool to room temperature, then slice and serve! Enjoy!