Greetings - I was just thinking about this tonight. I have seen butter mixed with melted chocolate but I have not tasted it. I am thinking about making fudge - a recipe using butter (there are recipes that don't use butter in the fudge) and trying that. Cannabutter would be nearly interchangeable but my only concern is the temperature might get too high and mess with the THC.
Good luck and give a few things a try - you never know when you might find something AMAZING that you can share with the rest of us!
BJT