I'm definitely not as much a butter aficionado as the author of the article is, just wanted to add that for me one of the best choices when it comes to European butter is the Irish Kerrygold. It's absolutely great butter, imo it's better even compared to more expensive French butters.
Related, one of my best memories related to butter, and a genuine good memory all around, was when my grandma was asking me to make butter while she was busy doing some other stuff around the house. It was easy enough and she knew that even city-boy me couldn't mess that simple thing up. It was very similar to what this guy is doing in this video [1]