If your baking recipe requires some ripe bananas and all you have is some near-green ones, a few egg yolks can save the day. Photo by Vicky Wasik.
Whether you like making banana bread, pancakes or muffins, Stella Sparks at Serious Eats has a trick you should keep up your sleeve: Raw egg yolks quickly ripen bananas. The amylase enzyme found in egg yolks turns the starch in unripened bananas into a combination of maltose and glucose, or liquid sugar. This makes the banana ripen in about 30 minutes so it softens up and gets much sweeter. So the next time you need to ripen some bananas fast, mash them together with the number of eggs the recipe calls for and wait at least half an hour. This trick doesn't help you if you're just looking to snack on a banana or make a smoothie, but there are other methods you can try for those situations.
Quick-Ripen Bananas for Baking Using the Power of Enzymes [Serious Eats]