In a large bowl, use a large wooden spoon and mix softened butter and sugar until it’s a nice creamy texture.
Beat in the egg, then add vanilla, salt and baking soda. Mix well with the wooden spoon
Add bananas to the mixture and mush and mix them in using the wooden spoon. If you have a potato masher, that works well too. If using chopped walnuts, stir them in as well.
Spoon mixture into a loaf pan (standard size is 8 1/2″ x 4 1/2″). Fill loaf pan about 2/3 full to the top. This is important as bread will rise during baking and needs some room. If you have extra batter, make an additional loaf or muffins.
Bake in preheated oven for about 1 hour. Use a toothpick placed into the center of the loaf to check for doneness. If the toothpick comes out clean, the banana bread is ready. If it comes out with batter still on it, bake another 10-15 minutes.