Dd used to eat banana and avacado mashed by spoon when she was little. I would freeze the left overs in a ice cube tray to prevent it from turning black but then dd could only eat it again by spoon or hold a very cold avacado cube.
I bought a popcicle tray the other day and mashed two very ripe bananas and a very ripe avacado with a potato masher, filled the trays and froze them. Dd loves them and because they are a bit chunky they don't drip or leak on the floor (very much).
I was thinking I could also add a bit of yogurt for sweetness but she seems to like them how they are.
Just wanted to share this healthy treat.