Every week, the nice Oberweis man delivers our milk and one container of heavy cream. It's my standing order. I intend to make homemade icecream once a week. It hasn't happened yet. As a result, we had four containers of cream that I did NOT want to waste, so I knew it was time to make butter.
I've done it before. It's super easy with a food processor. It takes all of about 5-7 minutes. Here's a great video.
And just because I don't want you to do what I did, please don't think it's a good idea to make butter while you have milk heating on the stove to make yogurt. This is what you will end up with: