Place the butter in the bowl of a stand mixer fitted with the paddle attachment and beat on low to medium-low until smooth, about 3 minutes.

Begin adding the sugar, a half cup at a time, keeping the mixer at the same low speed. Once about a third of the sugar is incorporated, stop the mixer and scrape the bowl with a rubber spatula. Return the mixer to the same speed, and add about 1/4 of the cream, mixing until incorporated.

Continue slowly mixing in this fashion (adding sugar and cream, scraping with a spatula periodically, and taking time to let the mixer run in between additions), until most of the sugar and cream has been incorporated.

Add the vanilla and salt, mix again and add the remaining sugar and cream. Continue mixing on medium-low (at the highest) for at least 5 to 10 minutes, if not longer, adding the food coloring halfway through the mixing time, if desired. The frosting will be quite light, creamy, and fluffy when it is done.

Store the frosting tightly covered at room temperature for up to 24 hours or refrigerate it for up to one week. Bring the frosting to room temperature prior to using.