I'm worried they will dry out and they are oh so moist right now.
Are you channeling your best self with this comment? (If you're not sure, check out our Code of Conduct.)
Are you kidding ... I would eat them now and serve something else to guest tomorrow !Or, probably best to refrigerate in an air tight container, bring to room temp before serving.Put a lock on the fridge overnight to keep prowlers out.Bacon brownies are making my heart flutter - good luck with them. (maybe post your recipe ... please)
To be safe I'd refrigerate them unless it was just for me. Try the trick for sandwiches. Wet a paper towel and wring it out well and spread them over the top before you seal the container.