To make the butter base, pour heavy cream into either a food processor or stand mixer with a whisk attachment.
Turn food processor or mixer on high until butter separates from buttermilk. It is a gradual process, and will go through three main stages. It will look like whipped cream, then curdled milk, then it will completely separate. It will be obvious when this happens.
Strain the buttermilk into a container and either reserve or discard.
Press the butter against a mesh sieve or squeeze through cheesecloth until no more liquid can be pressed out. Pour ice water over the butter, once it runs clear you are done.
To make any of the four butters, combine the ingredient with the butter in a bowl and mix. A fork is the best mixing method-or throw it back into the food processor to combine quickly.