This is the sort of thing I am talking about
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Cuisinart ICERFB Ice Cream Freezer Bowl - BizRate - Compare prices, reviews & buy - Price - Review
To make what I do work, I have the treats inside it, freeze it and the treats in our deep freeze and transfer it quickly into the "cooler" which fits it pretty snugly and I seal it. It sounds like more trouble than it is - I am just being explicit because every step is important. I tried it in a regular cooler. I tried adding the treats right before sealing up (they were just bought from the store, and not frozen rock hard). Those were both failures.