In the bowl of a stand mixer fitted with a paddle attachment, beat the butter on high until light and fluffy, about 4 minutes. Turn the mixer to low, add the powdered sugar, and mix until well combined. Scrape down the bowl and paddle, give the melted ruby chocolate a few stirs and make sure it’s not hot enough to melt the butter (if it is still too hot, wait a few minutes before adding!), then add it in. Turn the mixer to medium speed and beat for 2 minutes, until the mixture is smooth. Add the vanilla, heavy whipping cream, and salt and beat for another minute on medium.