Weekday Wonderings: Can we make a shampoo bar without cocamidopropyl betaine?

In this post on shampoo bars, Bella asked: Is it ok to make a syndet shampoo bar without cocamidopropyl betaine? Everyone makes it seem like an impossibility, but there is a company that makes them and they are sellilng very well and I don’t see that ingredient in their product. The company is Ethique, here…