In a saucepan, combine the cream with the tea leaves, sugar, cardamom pods, cinnamon stick, and cloves. Warm over low heat until it just starts to simmer, then turn off the heat and allow the tea to steep in the cream for 15-20 minutes. Strain out the solids. The liquid should measure out to 250 ml. If it's more, cook for a little longer. If it's less, add more cream to it.
Add the rusks to a bowl. Warm the strained cream again and pour it over the rusks, letting them sit for 2-3 minutes to soften. Use a spoon to break them up and mix well. Pass the mixture through a strainer once more, pressing to get as much liquid as possible while removing the rusk bits. The liquid should measure out to 250 ml (or close). Set aside to cool fully.
Using an electric mixer, whip the liquid whipping cream to soft peaks. Pour in the condensed milk along with the cooled chai rusk mixture, then continue whipping for 3-4 minutes until medium peaks form.
Transfer the ice cream base into your tin. Bloom the saffron in cold water, then swirl it over the top for a marbled look. Wrap tightly with plastic wrap to prevent freezer burn, and freeze for a minimum of 6 hours, or until fully set.