Heat the water, turmeric, ginger, fennel, cayenne, and cardamom together until it starts to boil. Reduce heat and simmer for 5 minutes.
Add the green tea and steep for 3 minutes.
Strain everything through a fine mesh sieve.
Add the honey and milk, and stir or blend in a blender until frothy.
Notes
You can use coconut milk here, but it is very rich, so I don't use a full cup. I use 1/4 cup full-fat canned coconut milk and an additional 3/4 cup water in the recipe instead of almond or oat milk.If you want a creamier coconut milk version, add up to 1/2 cup coconut milk and 1/2 cup water instead of 1 cup almond or oat milk.