Bring 3 cups of water to a boil in a saucepan. Add in 6 Earl Grey tea bags and turn off the heat. Let steep for 8 minutes, then remove and discard the tea bags and let tea cool completely.
In a large bowl, use an electric hand mixer to beat together 5 egg yolks, 2 tablespoons honey and 1/3 cup sugar at high speed for about 3 minutes, until almost doubled in volume, thickened, creamy and pale yellow. Add in 1 1/2 cups heavy cream, 2 cups mascarpone, 1 tablespoon orange zest and 1/2 teaspoon ground cardamom; beat on medium-high until the mixture reaches almost stiff peaks; it should look like a very thick whipped cream.
Quickly dip a ladyfinger in the cooled Earl Grey tea and place them side-by-side in an 8×8 dish until you have one single layer, breaking up ladyfingers as needed to fit, about 12 ladyfingers per layer. Top with half of the mascarpone mixture. Repeat with remaining ladyfingers and the mascarpone mixture. Loosely cover with plastic film and chill for at least 6 hours.
Just before serving, place 1 teaspoon ground chai masala, if using, in a small sieve and lightly dust the top of the tiramisu.