Johno loves jelly. I make it from fruit and fruit juices with gelatine leaves. When he was little, I used the baby fruit juices and warmed a bit to dissolve the gelatine then mixed it with more juice and some pureed fruit. If you do decide to have a go, don't use pineapple, it won't set for some reason. You can also do milk jellies to get milk AND fruit in them!
Blithering on about my jellies I didn't answer the question. If you make it quite solid, then give it to them in cubes to start with. Johno always loved the feel of it. When they can use a spoon its a good spoon food because it makes rude noises when you try and get it out of the dish!