Preheat your oven to 350 degrees F. Spray a 9x5 inch loaf pan with nonstick spray, or line with parchment paper. I prefer using the paper so that you can lift the bread out for easy slicing.

If you plan to add nuts, toast them now so they have time to cool. Add 1/2 or 3/4 cup chopped nuts (I like either walnuts or pecans) to a dry baking sheet. Bake at 350 for 5-7 minutes, stirring every 2 minutes. You will know they are done when they are very fragrant. Set aside to let cool.

In a large bowl or stand mixer, beat the butter until it is smooth, scraping the sides of the bowl. Add 1/2 cup brown sugar and 1/2 cup white sugar and cream together. This means beat it for about 2 minutes until it is fluffy, making sure to scrape the sides and bottom of the bowl.

Add 2 eggs and 2 teaspoons vanilla. Beat well until incorporated, scraping the sides.

In a small bowl, use a fork or potato masher to mash about 2 and 1/2 very ripe bananas. It should come out to about 1 cup.*  A little more or a little less banana, and you are still going to get banana bread. (More banana=more dense. Less banana does NOT make your banana bread not-moist.) 1 cup is the magic number for me. Add the mashed banana to the butter mixture and stir until incorporated.

Add 1 cup flour to the bowl, but do not stir yet. (You can mix the dry ingredients in a separate bowl but I am too lazy.)

Add 1/2 cup old fashioned oats to a blender or food processor. Blend until the mixture has turned into powder, if it's a little gritty that's okay. Add the oat flour to the bowl but don't stir.

Use a small spoon to stir 1 teaspoon baking soda, 2 and 1/2 teaspoons baking powder, and 3/4 teaspoon kosher salt into the flour. You don't want any clumps of salt or soda in your bread.

At this point, you can add 1/4 teaspoon cinnamon and 1/8 teaspoon each cloves and nutmeg. This bread is still really good without the spices, they are optional.

Stir the dry ingredients into the wet ingredients until incorporated, scraping the sides and bottom.

Lastly (don't forget!!) fold in the 1/2 cup sour cream.

If you want to add nuts, fold them into the batter now. (Next time I think I will save 1/4 cup to sprinkle on top of the bread before going in the oven. Just an idea!)

Pour the batter into the prepared pan and smooth out the top.

Bake at 350 for 55-65 minutes. Every oven is different and you are probably going to have to check it a few times. There is nothing sadder than undercooked banana bread, so I rely completely on the toothpick test: a toothpick inserted very deeply into the center of your bread (stick it right into the crack that has formed) should come out with no wet batter on it. Very moist crumbs are ok, as the bread will continue cooking just a bit once pulled out of the oven. The bread should look nice and brown on top and should be pulling away from the sides of the pan.

Let the bread cool completely (okay, well at least for 20 minutes or so) on a cooling rack before slicing into it. If you don't devour a warm slice immediately with copious amounts of butter, it's a crime against bananas everywhere.

Store covered on the counter for up to 2 days, then if there is by some miracle some leftover, I would stick it in the fridge.

Banana bread freezes beautifully. You can wrap an entire loaf in foil and then ziplock and freeze (thaw on the counter with the bag sealed) or you can slice it and wrap and freeze individual portions for when you need a quick fix. Let thaw on the counter in the sealed container. Toss thawed slices in the toaster for a minute to get rid of extra moisture.