Banana bread was invented to use up soft overripe bananas. If, from time to time, you’ve got a few extra bananas that are turning dark and soft, don’t throw them out. In just a few minutes, you can transform them into banana-bread batter.

You’ll need a standard loaf pan for this, about 9 by 5 inches and about 3 inches deep. You can often find them at garage sales and secondhand stores. Or you can bake two mini-loaves, one to keep and one to bring to someone’s house as a perfect little gift. If you go this route, begin checking for doneness after 40 minutes.

You can make this a day before you plan to serve it. Store it, wrapped in plastic wrap or in a resealable plastic bag, at room temperature — or in the refrigerator if you’re keeping it for more than a day. You can also freeze it whole, or in slices so you can grab a single serving and toast it. (It’s OK to put it in the toaster still frozen.)

Steps

1. About an hour ahead of time, unwrap the butter and place it in a large bowl. Use a table knife to cut it into 1-inch pieces, and let it stand at room temperature to soften.
2. Adjust the oven rack to the center position and preheat the oven to 350 degrees (325 degrees if you’re using a glass pan). Put a little soft butter on a paper towel, a piece of waxed paper, or a butter wrapper, and lightly grease the bottom and corners of a standard-sized loaf pan. (No need to grease the sides.)
3. Peel the bananas, and place them in a medium-sized bowl. Mash with a fork until they form a mostly smooth pulp, then switch from mashing to mixing as you drizzle the buttermilk directly into the bananas. (You can use the fork or a whisk.) Keep mixing until the mixture is completely blended, and then set this aside.
4. Crumble the brown sugar into the bowl with the softened butter. Use a handheld electric mixer at high speed (or if you don’t have one, use a whisk, with enthusiasm) to beat the butter and sugar together until light and fluffy. Use a rubber spatula to scrape the sides of the bowl a few times during this process. Add the eggs, one at a time, beating well after each addition. Add the vanilla extract, and continue to beat for another minute or two, until everything is well combined.
5. Combine the flour, salt, baking powder, and baking soda in a second medium-sized bowl. Whisk slowly to blend. Add about half of this dry mixture to the butter mixture, stirring it in with a wooden spoon. Then stir in about half of the banana-buttermilk mixture. Repeat with the remaining dry mixture, followed by the remaining banana-buttermilk mixture, stirring from the bottom of the bowl after each addition, just enough to thoroughly blend without overmixing.
6. Transfer the batter to the prepared pan, taking care to scrape all of it in with a rubber spatula. Then use the spatula to spread the batter evenly. Bake for 50 to 70 minutes, or until a sharp knife inserted all the way into the center comes out clean.
7. Remove the pan from the oven and allow the bread to cool in the pan for at least 15 minutes before removing it. (The best way to do this is to rap the pan sharply on the counter a few times to loosen the bread, and then let it slide out onto a cooling rack.) To avoid crumbling, wait at least 20 minutes longer to slice and serve.