INGREDIENTS 1 pint heavy cream (aka whipping cream)
Pour the cream into a quart-size jar & add your starter. Whisk briefly to combine and cover with a muslin cloth. Culture at room temperature for 12-36 hours. The cream is done culturing when it's a little tangy, has thickened slightly and smells sweet and tangy.
Once cultured, place cream in the refrigerator for about 1 hour to chill. Next, use a stand mixer (with a splash guard), blender or butter churner to churn your cream. The cream will whip into peaks (1-2 minutes), then become grainy (2-3 minutes). Keep whipping until the solid butter mass and liquid buttermilk are separated (4-5 minutes total).
Gently pour the butter and buttermilk through a muslin cloth-lined strainer over a bowl. Transfer the buttermilk to a jar and store in the refrigerator. Be sure to save 2 tbsp of buttermilk for culturing your next batch of cream.
Remove the butter from the strainer and place it in a bowl. Add 1/2 cup of ice water to the bowl. Using a rubber spatula or butter paddles, fold and press the butter into the ice water. It will quickly become cloudy as remaining buttermilk is drawn out into the water.
Pour off the cloudy water and add another 1/2 cup of ice water, pressing butter to remove more buttermilk. Repeat until the water is clear. This may take up to 6 washings. The butter will firm up towards the end, so you may find it easier to use your hands.
Once the butter is firm, sprinkle salt (if using) over the butter and knead it in with the spatula or your hands. Pack the dry, firm butter into a butter keeper, a jar, or roll it into a log using waxed paper or parchment paper. Alternatively, form your butter using a butter mold.
The butter will keep in the refrigerator for about 3 weeks or can be frozen for several months.
Image: Rebecca Siegel