Pour a tea cup of water into a saucepan along with the fennel seeds and cinnamon and bring to the boil. Once at boiling point turn down the heat and let it simmer for 2-3 minutes.
Add the teabag (if you use one) and simmer for another 1-2 minutes then turn off the heat completely and let it steep for a minute.
Remove the teabag and pour into a cup through a strainer/sieve.
Add sweetener to taste.