First thing is to pit the cherries. There are a few ways to do this. Of course there is the old stand by, the cherry pitting tool. You can also push the pits out with a nail or straw.
I prefer the smash method. It’s quick and quite cathartic. Remove any stems, and add the cherries to a large ziplock bag; the zipper ones work best. Using a meat tenderizer, smash the cherries. Don’t go all Hulk on it. Simply smash them so you can squeeze out the pits. Transfer the cherries to a bowl and push out the pits.
Add the cherries to a quart-sized mason jar.
Now for the vanilla bean. Vanilla beans are tricky because they are small and a bit slippery. You need a good knife when preparing one. The Kuhn Rikon knife is great for this. It’s sharp, and the silicone coating works well with the seeds. Simple trim off the ends of the bean and slice it in half, lengthwise. Then using the dull backside of the knife, scrape the seeds out of the bean. Transfer the seeds and the bean to the mason jar.
Add in the sugar and vinegar. Place the lid on the jar and give it a good shake. Let the jar stand in a cool spot for at least 24 hours. Then strain out the cherries and vanilla bean, reserving the syrup.