When I was a kid, our babysitter moved out to the country and bought a farm. One weekend we went to go stay with them and I remember being fascinated when she made homemade butter. I didn't know you could make butter. And the taste was incredible. Of course she was using fresh cream from a just-milked cow, and the cream was unpasteurized. But still. You can still make it at home and it'll taste better than what we can get in the American grocery stores. 
You can use a food processor or a mixer. I personally have not used the food processor. I like the mixer. Anyway, you want to use heavy or very heavy "whipping" cream. If you can get "vat-pasteurized" cream, it has a better flavor. If not, you can use the ultra-pasteurized commercial type. 
Since I just grabbed some of the grocery store cream, I like to lightly sweeten it by adding about a teaspoon of simple syrup while mixing. It doesn't make it "sweet," it just gives it a richer taste, and enhances the sweet cream. I also add a pinch of salt. Go light on the salt! You can always add more later. 
Mix on low-medium. It will first turn into whipped cream...
Then will turn yellow and you'll see the butter separate from the buttermilk.
When it looks like this, you can stop. 
Drain the butter from the milk (the milk is really good too! Sweet, not sour.)
At this point, you can do a couple of things. Eat it right away, or process further for longer term storage. I like to put it in a bag, then knead it to expel the rest of the moisture. If you're not going to eat it right away, then you should also "wash" it, by putting it back into the mixing bowl and mix for a minute with ice water. Drain the water and replace with clean water a few times until water stays clear.
Washed or unwashed - storage should be air tight. Plastic bag or wax paper is OK. You can also cut into chunks and put them in a jar and cover with clean water and store in the fridge replacing water once in a while. This will allow it to keep it's fresh taste. Can also be frozen.
Washed or unwashed - storage should be air tight. Plastic bag or wax paper is OK. You can also cut into chunks and put them in a jar and cover with clean water and store in the fridge replacing water once in a while. This will allow it to keep it's fresh taste. Can also be frozen. 
Enjoy!
