Soak 2 black tea bags and 4 crushed green cardamom pods in ½ cup hot water. Allow it to cool to room temperature—this will season your filling.
Combine 1½ cups broken digestive biscuits with ⅓ cup melted butter. Press into a springform pan and refrigerate for 15 minutes.
Beat 450g cream cheese with ½ cup sugar, 2 eggs, 1 tsp vanilla, and the cooled cardamom tea. Blend until smooth—do not overbeat.
Pour the filling over the crust. Bake at 160°C for 45–50 minutes in a water bath to prevent cracking. The center should be slightly jiggly.
Cool completely, then refrigerate for at least 4 hours. Top with whipped cream, a sprinkle of ground cardamom, and some crushed pistachios before serving.