Preheat oven to 350F (175C). Grease and flour a 9x5 inch loaf pan.
In a medium bowl, whisk together the flour, baking soda, salt, and optional spices (cinnamon, nutmeg).
In a separate large bowl, cream together the softened butter and sugar until light and fluffy.
Beat in the eggs one at a time, then stir in the vanilla extract.
In a small bowl, mash the ripe bananas.
Add the dry ingredients to the wet ingredients alternately with the buttermilk, beginning and ending with the dry ingredients. Mix until just combined. Do not overmix.
Gently fold in the mashed bananas and optional nuts or chocolate chips.
Pour the batter into the prepared loaf pan and spread evenly.
Bake for 50-60 minutes, or until a toothpick inserted into the center comes out clean.
Let the bread cool in the pan for 10 minutes before transferring to a wire rack to cool completely.
Optional Tips: For a richer flavor, brown the butter before creaming it with the sugar. If buttermilk is unavailable, substitute with regular milk plus 1 teaspoon of lemon juice or white vinegar. Allow the mixture to sit for 5 minutes before using. For a streusel topping, combine cup flour, cup brown sugar, and 2 tablespoons cold butter; crumble over the batter before baking.