Pour the cream into a jar or bowl.
Add 2 tablespoons yogurt. Stir gently until well combined, then cover.
Set the bowl in a warm (around 70*) spot. Leave it out for at least a couple of hours. Check it often and test for flavor.
Beat the cream with a stand mixer or hand-held mixer until the buttermilk separates from the fat.
Alternatively, you can place in a jar and shake firmly.
As the butter separates from the buttermilk pour off the liquid (save it for tomorrow’s pancakes) and continue to beat, getting out as much of the buttermilk as you can.
When most of the buttermilk has been released add ½ cup very cold water and continue to mix on low.
Pour off the liquid and repeat until it’s nearly clear.
While still in the bowl knead the butter by hand as you would bread dough.
Pour off any remaining liquid as it accumulates.
Knead in the salt. Taste and add more if desired.
At this point your butter is ready to use.
