In a medium pot add in cinnamon, coriander seeds and nutmeg and place on medium heat for 1-2 minutes to toast spices until fragrant.
Pour in 1 cup cold water along with the peels of the orange, lemon and lime and bring to a gentle bubble and simmer for 5 minutes.
Add in orange bitters and vanilla essence and let it gently bubble for 5 more minutes.
Add in the brown sugar and let it gently bubble for five more minutes.
Add in the juice of half the orange, half the lemon and half the lime and let it cook through for a minute on the heat before taking off heat.
Let the syrup cool to room temperature before straining and placing in a sterilised jar in the fridge.
To serve, pour in 45ml in a glass, top with ice and then soda water and mix through. Adjust syrup to taste.