Allow whipping cream to reach room temperature. This starts the separation process.
Using the wire whisk attachment, pour whipping cream into mixer bowl, and start mixing on speed 1 and gradually work up to speed 10. Do this for 3 minutes. This will get messy.
The butter/fats will start to stick to the whisk, at this time, drain the buttermilk from the bottom of the mixing bowl.
Pour a small amount of the ice water (do not get any ice into the mixture) over the butter and into the mixer. Run the mixer on medium speed. This will get messy. This process is draining all of the buttermilk off the butter.
Drain excess liquid at the bottom of the bowl. And repeat the ice water process until the liquid at the bottom is completely clear and not cloudy. Drain any remaining water from mixing bowl.
Using a silicone spoon or spatula, remove butter from wire whisk and press against the sides of the mixer to remove any excess liquid. This is very important because excess liquid will cause the butter to rapidly spoil. If you're having a hard time with the spatula, this can be done with a cheese cloth.
Stir salt and herbs to your taste and store in an airtight container!