I made a medium size jelly jar of this butter and couldn't believe how good this was. It reminded me of the butter we used to make at my grandma's house when I was a child.Better than the butter you buy at the store.
Pour the whipping cream into a jar leaving a few inches at the top of the jar. A jelly jar or a mason jar will probably work. But if you use the jelly jar you will probably need to cover the top of the jar with a piece of plastic wrap before twisting the top back on it tightly.
Now this will be the hardest part of the process. Just shake the jar vigorously for up to 15 to 25 minutes. You will feel the cream thickening during the later part of the shaking process. Just keep shaking till it gets to the desired creaminess / thickness you prefer. Once you have it then all you do is add the salt (optional of course). At this point just mix it and if you want you can place the butter in a bowl or other container of your liking but you can also just leave it in the jar. You might also consider adding in any flavoring or spices to make a flavored butter. I made some ranch flavored butter for mashed potatoes for dinner. It was delightful.
This butter does need to be stored in the fridge and will last for up to two weeks,if the kids don't polish it off long before then. Enjoy!