Add everything except the vanilla extract to a pot and stir. Bring to a boil, then to a simmer for 30 minutes.
Remove from the heat, crush cherries in the pot, add vanilla extract and stir.
Press through a sieve and store liquid in a jar, jammy cherries in another. Enjoy!
Notes
Store cherry coffee syrup in a sealed jar in the fridge for up to 1 week. The leftover cherries should also be kept in the fridge, but they’ll have to be used within a few days.