Yes, it's true. You can make a substance very like soft-serve ice cream from nothing but frozen bananas and milk. My s-i-l told me about this a couple weeks ago, and we finally tried it ourselves tonight, and Oh My Word, it was sooooooooooooo good! Thank you, Erika!!!
Frozen Banana "Ice Cream"
2 Tbsp milk (approximate)
Wait for the bananas to be ripe, as in they need to have brown spots on the peels. Peel them, break them into chunks (about 1 inch each), and freeze them until they are not soft anymore. Stick them in a food processor, pour in a bit of milk (I didn't measure, but 2Tbsp is my guestimate), and blend until it's miraculously become ice cream-like. You might have to stop and scrape down the sides during the blending.
You can add flavorings to this -- we tried cocoa powder tonight, and 1 Tbsp made it chocolate-and-banana flavored, so next time we might try 2 Tbsp. We also thought of using strawberry jam, but haven't tried that yet.
Two bananas made enough for each of my 3 kids to have a pretty big serving, almost double the size of the ice cream servings I usually give them. Two bananas made enough for a big serving each for Cowboy and myself. Next time I'm going to try 3 bananas for the 5 of us, as this doesn't re-freeze -- you have to eat it all right when you make it.