- Brew Thai tea and let steep for 5-7 minutes. Remove tea bags or strain loose leaf. Stir in 1/4 cup sweetened condensed milk and rum (if using). Let cool slightly. 
- In a separate bowl, whisk together mascarpone cheese, remaining 1/4 cup sweetened condensed milk, heavy cream, and granulated sugar until smooth and creamy. 
- Lightly dip each ladyfinger into the cooled Thai tea mixture. Do not over-saturate; ladyfingers should be moist but not soggy. 
- Arrange a layer of tea-soaked ladyfingers in the bottom of a baking dish (approximately 9x13 inches). 
- Spread half of the mascarpone cream mixture evenly over the ladyfingers. 
- Repeat layers: Arrange another layer of tea-soaked ladyfingers over the cream, followed by the remaining mascarpone cream. 
- Cover the dish with plastic wrap and refrigerate for at least 4 hours, or preferably overnight, to allow the flavors to meld and the dessert to set. 
- Before serving, dust generously with cocoa powder. Garnish with star anise or orange zest, if desired. 
- Cut into squares and serve chilled. 
- Optional Tips: For a stronger tea flavor, reduce the amount of water used to brew the tea. If rum is not desired, substitute with additional Thai tea or a teaspoon of vanilla extract. For a richer flavor, use full-fat mascarpone cheese and heavy cream. Ladyfingers can be store-bought or homemade.