Pour any amount of heavy cream you like into a jar or food storage container that has a tight fitting lid. For little kids you can reuse baby food jars. You can use just a few tablespoons of cream for something small like a baby food jar, or up to a pint for a larger jar.
Add a pinch of salt and seal tightly. (Some recipes also suggest adding a clean marble to speed up the process – if you do this,don’t forget to remove the marble before eating yourhomemade butter!)
Shake! This is the fun part, shake the jar till you feel the cream thicken and coat the jar, then shake some more. You will know it is complete when you suddenly go from having a jar full of whipped cream, to having a thin liquid sloshing around a mass of butter. You may feel like the job is done once the heavy cream turns into whipped cream, but keep shaking! The shift from cream to butter and buttermilk is very dramatic. Strain the buttermilk into a separate container and store both in the refrigerator. You can use the buttermilk for biscuits, waffles, ranch dressing, etc.
This butter will keep in the fridge as long as any butter you purchase in the store. Enjoy!