Start with some cream. You cannot use store bought milk that has been homogenized. Buy just the cream. We use heavy cream because that's what Brindle gives us. Use what's cheaper either heavy or whipping cream. I don't think it will matter.
What I do is use the milk from the day before. That way there has been plenty of time for the milk to separate and it is as fresh as possible. This is what it looks like after the first day in the fridge.
The most important thing is to start with the cream at a temperature of 60 degrees. Get your food processor out and put in your metal blades. Pour in the cream to the maximum fill line. Put the lid on and start it on high for 4-5 minutes. If you watch the process, you'll notice that the cream will turn to whipping cream, then break down, and then turn to butter. Usually by 5 minutes it's ready, but it just depends on your machine, cream, and the temperature of the cream. This is what it will look like when done.
Pour out the milk (I give it to the pigs), and dump the butter into a separate bowl. I use a pan with a handle because it is easier for me to hold and work with the butter. What you want to do is smash up the butter. You are trying to get all the buttermilk out.
Once you think you've got it as drained as possible, get a cookie sheet, wax paper, and a tablespoon measure. Put a sheet of wax paper down on the cookie sheet and start scooping tablespoons of butter. Pack the butter into the spoon with your finger. This will help get more liquid out. Scrape the spoon against the edge of the bowl to get an exact tablespoon.
After I have all the butter divided up, I place the cookie sheet in the fridge for about an hour. I want the balls to be hard and cold. Once they are very cold, I put all the balls into a plastic container and put them in the freezer. This helps the butter keep longer (especially since my milk is not pasteurized). Another plus to making the tablespoon balls is that the butter comes to room temperature much faster.
I hope you'll give it a try and let me know how it goes. The perfect thing to make with your butter is grilled cheese sandwiches!
If you'd like to try your hand at making butter like we do, contact me to arrange for a visit. The milk is free if you bring a container. I do ask for a donation if you can afford it. I'll even teach you how to milk a cow.