Why would you want to make your own butter? Because it tastes better! And it's easy. All you need it heavy cream, salt, and a mixer-although you can get away without using the mixer. If you are using a mixer, you will need to cover it with plastic wrap, unless you're really into cleaning up splatter. Pour heavy cream into your mixer. It doesn't have to be fresh. It can be close to its expiration date. This time I used 3 cups because I had an open container and an unopened one.