Because there are only two options when you have a couple of nasty-looking bananas lying around:
throw them out or bake banana bread.

Recipe adapted from Averie Cooks.

Gather:
55g butter (melted)
3/4 cup caster sugar
1/2 cup packed dark brown sugar
2 large eggs
1 tsp vanilla extract
170 grams yoghurt (low-fat vanilla Jalna works well, but anything will do. Greek if you’re not into sugar, King Island vanilla bean if you are?)
2 or 3 very ripe bananas, mashed (or as many as you have lying around)

2 + 1/3 cups plain flour
1 tsp baking soda
1/2 tsp salt

Optional: Walnuts, sultanas, desiccated coconut, oats, chocolate chips, chopped dates. That sort of thing.

Then:

1. Butter a 2L, square Pyrex baking dish (or a large loaf tin) and preheat the oven to 175º C.
2. Mash the bananas.
3. Melt the butter in the microwave (why dirty a saucepan?)
4. In a medium bowl, sift together the flour, salt and baking soda, and set aside.
5. In a large bowl, use a wooden spoon to mix the melted butter, sugars, mashed banana, eggs, vanilla and yoghurt.
6. Add the sifted dry ingredients (flour, baking soda, salt) and stir until completely and utterly combined. If you’re sick of plain banana bread, add any of the optional ingredients now. NB. If you’re using desiccated coconut, add some more liquid to the batter — a few more tablespoons of yoghurt, for example.
7. Spatula (it’s a verb because I say it is) the batter into the prepared baking dish (or loaf tin) and bake for 50–60 minutes. (You can turn the oven down to 160 or even 150 if it’s getting too brown on top.) It’s ready when a bamboo skewer comes out clean (not covered in banana-y goo).

Notes:
I generally leave this on a cooling rack but IN the baking dish to cool, so it stays together when I flip it out, which traps all the steam inside and keeps it nice and moist*.

BONUS: You can freeze this stuff indefinitely. Just slice it up into snack-sized portions, wrap them in cling wrap and stack them in the door of the freezer. When you get snackish, grab a piece and either microwave with the cling wrap on (again, to keep in the moisture) or just eat it straight from the freezer (it’s surprisingly not rock-hard and not tooth-assaulting). OR smash it up and put it on ice-cream.**

*I hate That Word too, but look: no other word does the same job when you’re talking about baked goods.
**This is my advice for any sugar-based recipe that looks wrong/you made too much of.