Add the whipping cream and brown sugar to a large mixing bowl or the bowl of an electric mixer.
With a whisk attachment, beginning beating the cream and sugar together on medium speed. At first it will be frothy and foamy. After about 2 minutes, it will look slightly thickened, but still very soft and floppy.
Pause the mixer, and add the cinnamon, sea salt, and vanilla (if using). Beat on medium speed another 1-2 minutes, or until the whipped cream is fluffy and voluminous and can hold a soft peak.
Serve the whipped cream immediately or refrigerate in a sealed container until ready to serve.
To pipe the whipped cream, transfer it to a piping bag fitted with an open star tip, then chill in the fridge for 15-20 minutes before piping.