Make the chai syrup: In a small saucepan, combine the water, sugar, tea bags, cinnamon stick, cardamom, cloves, ginger, and black pepper.
Bring the mixture to a gentle simmer over medium heat, stirring until the sugar dissolves.
Reduce the heat to low and simmer for 5 minutes to infuse the spices and tea.
Remove the pan from the heat and let the syrup steep for 5 minutes more.
Strain the syrup into a jar or heatproof container, then stir in the vanilla extract. Let it cool slightly.
To serve, pour 1 to 2 tablespoons of chai syrup into each mug, then add hot brewed coffee.
Stir in milk or cream if desired, and top with a pinch of ground cinnamon for garnish.
Notes
Adjust the amount of syrup to taste. The chai syrup can be stored in the refrigerator for several days in a sealed container. Use milk, cream, or a dairy-free alternative if preferred.