Pour the cream into your Vitamix (or blender).
Select Variable 1 on the Vitamix and slowly increase speed to Variable 10, then High. If you are using a traditional blender, start low and then go high.
Blend until the mixture is thick and you hear a change in the sound of the blender.
Stop the blender and scrapes down the sides with a spatula to bring the cream into the center.
Reset the Vitamix to Variable 5 (medium on a regular blender).
Turn the blender on and blend for about 5 seconds, stop and scrape sides down again.
Keep repeating this process several times until you see a fluid start to appear. You will know when the butter is forming.
Blend for a few more seconds until solid butter sets up in center of container.
Place butter in a fine mesh strainer to drain. Work butter with a spatula or your hands to remove as much liquid as you can.
Remove butter to a bowl and add salt to taste.