Combine water, cinnamon, cardamom, ginger, cloves, pepper, and salt in a medium saucepan.
Bring to a gentle simmer over medium heat. Cover and simmer 5 minutes to bloom the spices.
Stir in the loose black tea. Simmer 2 minutes, then turn off heat and steep 3–5 minutes.
Strain the spiced tea through a fine-mesh sieve back into the saucepan to remove solids.
Whisk in coconut milk, sugar, and vanilla. Warm until steaming, not boiling, then taste and adjust sweetness.
Pour into mugs and serve hot. Dust with a pinch of cinnamon if you like.