Place apple cider in a small saucepot over high heat. Boil until apple cider is reduced down to 2 oz (feel free to eyeball this, but you should have about 1/4 cup left when done).
Combine concentrated apple cider with all other ingredients (honey, extra virgin olive oil, apple cider vinegar, mustard) in a mason jar. Shake vigorously to combine.
Use immediately or store in fridge for up to 1-2 weeks.