procedure
1. pour 1/3 cup of heavy cream into a clean jar. Cap the jar.
2. Shake the jar. Take turns shaking; you may need to shake for 15 to 20 minutes. The cream will start looking like cottage cheese (whipped cream ).Continue shaking.
3. you will note a separation of solids and liquids.
4. The solid is butter, and the liquid is buttermilk.
5. Pour off the buttermilk. Add salt to the butter for more flavor. Try the butter on crackers.