Preheat your oven to 300°F (150°C) and gather a deep dish or roasting pan for the water bath.

In a medium saucepan, combine heavy cream, milk, and Thai tea mix over medium heat. Heat until it begins to boil, then remove from heat and cover to steep for 5-10 minutes.

Carefully strain the mixture through a fine-mesh sieve into a clean bowl, discarding the solids.

In a separate heatproof bowl, whisk together egg yolks and sweetened condensed milk until smooth and creamy.

Slowly drizzle the strained cream mixture into the egg yolk mixture while whisking vigorously to prevent scrambling.

Pour the custard mixture into individual ramekins, filling each about three-quarters full. Place the ramekins in your deep dish or roasting pan, then fill the pan with hot water halfway up the sides of the ramekins.

Transfer the filled pan to the preheated oven and bake for 25-30 minutes, until the edges are set but the center still jiggles slightly.

Remove the pan from the oven and let the ramekins cool at room temperature for about 30 minutes. Cover with plastic wrap and refrigerate for at least 2 hours.

Just before serving, sprinkle granulated sugar over the top of each custard and caramelize using a kitchen blowtorch.