What you'll need:
stand mixer with whisk attachment (dough hook optional)
heavy whipping cream
How to do it:
Attach the whisk and pour some cream into the stand mixer. Add however ever much you want. I started with half a pint. The more cream you use the more butter you'll get. Now turn it on. I have a KitchenAid mixer and put it on speed 4 (about medium).
Soon the cream will start the thicken and look a little something like this.
Keep it going!
Now it's starting to look more like butter.
You might want to do a little something like this...
Let it run for just a bit longer to separate the butter and buttermilk.
Ta da! Now you have butter (and buttermilk)!
Strain the butter from the buttermilk. If you're planning on using the butter right away you're done. However, if you aren't, you need to rinse it so that it doesn't go rancid. There are two ways to do this. I tried both and preferred using my hands.
Grab the butter and kneed it under the faucet with cold water running. It has to be COLD water so the butter doesn't melt. Kneed the butter with your hands under the cold water until the water rinses clear.
Instead of using your hands you can kneed the butter in your mixer with the dough hook while adding ice cold water. The water must be cold to prevent the butter from melting. Kneed butter until water washes away clear.
Now you have homemade butter and buttermilk!