How to make butter

Step 1: Get yourself some cream. Heavy cream. And some sort of whipping utensil (a stand mixer would be ideal, but I don't have one so I used a hand-held electric mixer. If you're feeling particularly vigorous, or in need of some exercise, you can whip the cream by hand with a whisk or even shake it in a large jar.)

Step 2: Whip the cream. Here it is at stiff peaks...keep going.

Keep going...you can see that it's already turning yellow.

Something's definitely starting to happen here.

Stop! You have achieved separation! Now the butter solids have separated from the liquid ("buttermilk"), and you have little bits of butter. Don't whip past this point!

Step 3: Shape the butter. But first, you need to remove all the buttermilk, or your butter will go rancid quickly. You can do this by rinsing and kneading the butter in very cold water, then draining the water and adding fresh cold water, repeating until the water runs clear and no buttermilk remains.

Now you can form your butter into a ball, a log, a stick, or...

Step 4 (optional): Put the butter back in the bowl and whip for a few more seconds until the butter is light, fluffy, and spreadable.

Package, refrigerate, and enjoy!

Note: I ended up with 6 oz butter from two cups (16 oz) heavy cream. That's about a stick and a half. Clearly, making butter is not any more economical than buying butter from the store, unless you get a super deal on cream, but it's way more fun.