Using a fork, mash the bananas until they are well mashed, with small pieces of bananas for texture. Set aside.
Next, in a separate bowl, use a hand mixer (or a standing mixer) to cream the unsalted butter and granulated sugar together until light and fluffy. Add in the eggs, and then continue to cream the mixture until combined.
Add in all purpose flour, baking soda, and salt. Mix until it’s well combined (it will be very thick).
Lastly, add in the vanilla extract and the mashed bananas. Mix until all of the bananas have been incorporated into the bread batter.
Spread 1/3 of the banana batter into the bottom of the prepared bread pan. Sprinkle half of the cinnamon sugar mixture over the batter (yes, it’s a lot of cinnamon sugar, but it’s necessary). Top with 1/3 of the batter, gently spreading into an even layer. Sprinkle the remaining cinnamon sugar on top. Top with the remaining 1/3 banana bread batter. Gently spread into an even layer.
Using a knife, swirl the batter 4-5 times.
Bake at 350 degreed for 35 minutes. Then, lower the temperature to 325 degrees and continue baking for 20-25 minutes, or until a cake tester comes out clean.**
Allow the bread to cool for about 10-15 minutes in the pan. Then remove the banana bread from the loaf pan and allow it to continue cooling on a wire rack.
Serve the bread warm, room temperature, or cold. Also, I like to spread a little butter on mine.