Heat a medium saucepan over high heat. Add water, cinnamon stick, cloves, cardamom pods, black peppercorns, fennel seeds (if using), and ginger. (See Note 2) Bring to a boil and add the tea bags or leaves.
Reduce the heat to medium-low and simmer gently for 7-10 minutes, depending on how strong you’d like the tea and spices. It will turn a deep burgundy color and reduce slightly.
Add milk and sugar and stir. Raise the heat to high (or allow the milk to come to a boil on its own, as I do on any given day). Reduce the heat to medium and simmer for another 5 minutes.
When ready to serve, raise the heat to high and allow it to come to a rolling boil for 1-2 minutes, depending on how 'cooked' you like the milk. (See Note 3) If you’d like, use a ladle to aerate the chai to deepen the flavor and make it creamier.
Pour into cups through a strainer and add more sweetener, if desired.
