Stand mixer with whisk attachment (or hand mixer or food processor)
Mesh sieve (optional)
Large bowl for ice water
rubber spatula
Parchment paper or butter crock for storage
Ingredients
1quartheavy creamnot ultra-pasteurized for best results
4tablespoonsplain Greek yogurt with live cultures
Sea saltto taste (optional)
Instructions
Combine the heavy cream and Greek yogurt in a large bowl. Stir until fully mixed. Cover and let sit at room temperature for 48 hours, or until thick like yogurt.
Pour the cultured cream into a stand mixer fitted with the whisk attachment. Mix on medium speed, increasing to high, until the butter separates from the buttermilk.
Drain off the buttermilk and reserve for baking if desired.
Transfer the butter to a bowl of ice water. Gently knead and rinse until the water runs clear, changing the water as needed.
Stir in sea salt if desired. Shape and wrap in parchment paper or store in a butter crock or airtight container in the refrigerator.