Mash 2 ripe bananas in a mixing bowl until completely smooth and free of large chunks. Add 1 cup plain Greek yogurt, ½ cup natural peanut butter (xylitol-free), and ¼ cup water, then blend or whisk thoroughly until the mixture becomes creamy and uniform. Pour the mixture into a loaf pan lined with parchment paper and spread it evenly with a spatula to create a smooth surface. Freeze for 2–3 hours, or until fully firm. Once set, let it sit at room temperature for a few minutes to soften slightly,