Here’s a project: Let’s say you are stuck inside because it’s 6° outside and your children are climbing the walls with their endless supply of energy. How to exhaust them? Take a jar with a tight lid, pour in a cup of heavy cream, and tell them you are holding a contest to see who can shake the jar the longest. After about 10 minutes, they will get sick of this and go back to flinging themselves off of the sofa, but by then you are almost halfway there. Take over, keep shaking, and - lo and behold – you have made yourself some butter. No churn required.
Inside the jar, you will have a soft lump of butter surrounded by buttermilk. You will want to drain the butter milk and rinse the butter a few times (leaving buttermilk in the butter can make it go sour). Depending on its consistency, you can put it into a cup, or shape it into a log. Add salt or herbs if you like, and refrigerate or freeze. Or feed it to your children on toast as a well-deserved snack for all that shaking.