I do different layers to keep in interesting. Some things I use are cream cheese. Pumpkin, baby food turkey, veggies, green beans, peanut butter, maybe a thin layer of her food or small treats, plain yogurt, I guess what ever is around the house and ok for Gwen to eat. LOL. I always freeze it because it takes her longer to lick through it that way. There are a lot of ideas on different websites. I think Kong website even has ideas.