Ingredient

Banana

One of the few fruits that ripens properly after picking, and keeps going relentlessly. For baking you want them well past the point you would eat them — black-skinned bananas are sweeter and mash to a smooth puree.

Sourcing
Buy at the ripeness you need in two days, not the ripeness you want now. Supermarkets sell overripe bananas cheaply, which is the baker's bargain.
Varieties
Cavendish, Plantain, Lady Finger, Red banana
Quality cues
For eating, yellow with a few freckles. For baking, the blacker the better as long as the fruit inside is not fermented or leaking.
Substitutions
Plantain (for cooking), Apple sauce (in baking)
Storage
Room temperature, away from other fruit. The fridge blackens the skin but holds the flesh, which is a fair trade once ripe. Freeze peeled for baking and smoothies.
Shelf life
2-7 days depending on ripeness at purchase; months frozen
Nutrition

Per 100 g

Calories
89 kcal
Protein
1.1 g
Fat
0.3 g
Carbs
22.8 g
Fibre
2.6 g
Sugars
12.2 g
Sodium
1 mg

From USDA FoodData Central (#173944). Raw, edible portion.