Place the plums in a glass jar or glass container along with the sugar and the seeds of the vanilla bean. Using a muddler or the handle of a wooden spoon, mash the fruit until it is fully incorporated with the sugar. Add the vanilla beans seeds & pod.
In a small sauce pan bring vinegar to a gentle simmer. Pour the vinegar over the plum mixture and seal tightly. Shake the mixture a couple of times and refrigerate for 24 hours or up to a week depending on how strong you want the flavor to be.
When ready to serve, strain the fruit mixture using a fine mesh sieve or cheesecloth.
Mix equal parts shrub with club soda over ice. Add more or less to your liking. Serve and Enjoy!
