Whip the cream

• Pour the cold heavy cream into the bowl of the stand mixer.
• Whip on medium-high speed until it thickens into whipped cream.

Keep whipping until the butter separates

• Continue whipping; the cream will break and separate into butterfat and buttermilk.
• Scrape down the sides as needed.

Drain the buttermilk

• Stop the mixer once a solid mass of butter forms.
• Pour off the buttermilk and reserve it for another use.

Rinse the butter

• Add cold water to the bowl and knead the butter with a spatula.
• Drain the cloudy water and repeat until the water stays clear.

Season and store

• Press out any remaining liquid, then work in the salt if using.
• Shape the butter and keep it refrigerated in a sealed container.