Recently, I have put three enrichment/treat toys on rotation with a similar recipe inside them and it has been working well. I usually make up two of the toys daily, and just change around which two are used each time. I have been doing this over the last month or so, and Diego seems to really enjoy it. Inside the toys I use his usual dog food, which currently is Orijen Adult, some of the Omega Plus Fish Oil and a tiny bit of peanut butter. I feed these toys instead of his breakfast, and this makes sure he isn't getting overfeed or too many extra treats.
The first toy is the mainstream Kong toy. This is one of the first toys that was put on the market as a tough toy, that can be filled with food and treats to entertain your dog. I purchased my Kong online second hand (although never used as it was still in its packaging, it had been sitting around their home for several years) back when Diego was a puppy. This has been well loved, and lost multiple times but it always finds a way back to our collection. With the Kong, I put peanut butter in the top hole as a plug, and then fill the rest with food. Once full, I add a couple of squirts of the fish oil, and then close up the bottom with more peanut butter. I let this sit while I am getting ready in the morning, and during Summer I would put it in the fridge. This lets the oil sink in a bit more to make it less likely that the kibble would just fall out.