Peel the onion and roughly chop it into small pieces.
Place onion in the clean jar (also add optional extra ingredients now) then top with enough honey to cover. If your honey is too solid, very gently warm it until it starts to become liquid before adding it to the jar.
Leave to infuse in a cool place, out of direct sunlight, for twenty-four hours to up to four days. If the syrup becomes a little fizzy; it is just fermenting. As long as it does not smell unpleasant or "off" it is fine to consume. If you need to use it sooner, you can start skimming teaspoons from the top of the jar after thirty minutes of making it.
When infused, place a funnel on top of a clean jar with a sieve atop that. Strain the syrup into the jar, squashing the plant matter with the back of a spoon to make sure you get every last drop! Alternatively, you can leave the plant matter in the jar and consume it as well.
Label and store your cough syrup in the fridge for up to two weeks.
