In a saucepan, mix milk, cream, tea leaves, sugar, and your choice of whole spices. I recommend cinnamon, cardamom, and ginger, but feel free to include other spices like cloves or black pepper.
Heat on low and let the mixture infuse for 5-8 minutes. If your tea leaves tend to get bitter, reduce the cooking time.
Strain the infused milk-cream mixture over a bowl of white chocolate while it’s still hot.
Let it sit for a few minutes to melt the chocolate, then whisk until the ganache is smooth and fully combined.
Whip the remaining cream in a separate bowl until medium peaks form. Be careful not to overwhip, as the cream will be folded into the ganache later.
Once the ganache cools to room temperature, gently fold it into the whipped cream in two additions. Use a silicone spatula to avoid deflating the whipped cream.
Transfer the mousse to a piping bag for easy assembly.