Pour the heavy cream into the bowl of an electric mixer and begin whipping at a low speed until it slightly thickens.
Gradually increase the speed to medium-high, continuing to beat the cream for approximately 5 to 7 minutes. Periodically scrape down the sides of the bowl to ensure even mixing.
As the whipping progresses, the cream will transition beyond the whipped phase and begin to separate into solid butterfat and liquid buttermilk.
Once fully separated, transfer the butter to a clean surface, reserving the buttermilk for later use.
Knead and press the butter by hand to expel as much residual liquid as possible.
Rinse the formed butter thoroughly under ice-cold water until the rinse water runs clear.
Season with salt according to preference.
Store the finished butter in an airtight container or wrap it in parchment paper. Keep refrigerated and consume within 10 to 14 days.