I have tried this out because I got a bit obsessed with learning how to make every coffee drink during the pandemic. The way I did it was a double shot of espresso, a decently sized pat of good quality unsalted butter, and a little bit of hot water. The reasoning was that the butter would accentuate the naturally occurring oils of the espresso and lead to a richer crema on the resulting americano which was true. I thought it was actually pretty good that way, but I also love coffee in any form. It also wasn’t something I’d go out of my way to drink again. I also imagine this would do some bad things to your intestines if you drank this every day. If you want a delicious buttery coffee, a good quality whole fat milk is a much better option. As for health claims, I think it’s kind of insane that anyone says drinking literal butter could possibly be good for you, and even more insane that people believe it. It feels like an over-reaction to anti-fat propaganda from the sugar lobby where we went from “Maybe eating some fat in your diet isn’t a bad thing” to “YOU MUST EAT AS MUCH FAT AND OIL AS HUMANLY POSSIBLE.”