My Mother's Shitzu Has Bladder Stones And Is On Royal

My mother's shitzu has bladder stones and is on Royal Canin SO. They haven't determined the type of stones yet, we go back in a month for an X-ray to see if being on this diet has dissolved them. My question, Do you have any ideas on making treats from the canned version? I've made some from the dry by grounding and adding water and then baking. The dog use to get a Kong with peanut butter when left in a crate and it seems to be a big void for her not having that. Any ideas on what we could put in her Kong that might make her happy.