Add your whipping cream to the mason jar and screw on the lid tightly. The amount of cream doesn't really matter, you'll end up with more or less butter depending on how much you use. Don't fill the jar less than 1/4 full or more than 1/2 full (if it's too full it doesn't have enough room to move around and agitate the butter out). 

Keep shaking! The cream will whip up to thick whip cream and you keep going. Once the cream breaks you'll have pieces of butter floating in buttermilk. Shake until it happens (the butter will be obviously yellow). It can take 15+ minutes, so don't lose heart.

Once your butter and buttermilk have separated, place a fine mesh strainer over a large bowl and pour the contents of the jar into it. Save the buttermilk that falls into the bowl for cooking (like buttermilk biscuits), keep it in the fridge until you are ready to use.

Use your hands to remove the butter from the strainer and press it into a ball. 

Turn your tap water onto cold and gently press the ball of butter in and out of shape to help press out the extra buttermilk. Do this for a few minutes or until you don't see anymore buttermilk come out. 

You can salt your butter if you'd like (we really like it salted, especially if you are putting it on fresh bread). I generally add a scant 1/4 teaspoon per 1 cup of butter, but feel free to add to taste. If adding salt, just mix it in. 

The butter is now ready to use! Enjoy with fresh bread or over your favorite waffles. If you are doing this with kids who just want to try it, you can also spread if on a cracker to try.

We leave this butter out on the counter a few days to keep it soft but if you won't use it that quickly keep it covered in the fridge or freezer.