Preheat the oven to 300°F and prepare some hot water.
Combine heavy cream, milk, and the Thai tea mix in a saucepan and bring it to a boil over medium heat, stirring occasionally. Once the mixture comes to a boil, remove it from heat and let the Thai tea steep for 5-10 minutes.
After steeping, strain the cream and milk mixture using fine mesh strainer or a strainer layered with a couple sheets of cheesecloth. Discard the tea leaves.
In a heatproof bowl, add the egg yolks and condensed milk and whisk until well combined. To the mixture, slowly drizzle in the strained Thai tea cream mixture while whisking until all has been added. Gently whisk until well combined.*Make sure to add the hot Thai tea infused cream slowly to prevent scrambling the egg yolks. Read more in post.*
Portion the mixture into 3 (8 ounce) ramekins and place them into a deep dish pan or cake pan (at least 2 inch deep). Fill the pan with the prepared hot water, half way up the side of the ramekins and bake the crème brûlée for about 25-30 minutes or until the edges are set and the middle is jiggly.
Carefully remove the crème brûlées out out of the water and let them cool at room temperature until they're only slightly warm to the touch. Then chill them in the fridge for at least 2 hours or up to 3 days.
Once the crème brûlées are set, sprinkle a small amount of granulated sugar on top of and roll it around the entire surface. Torch the crème brûlées until golden brown like caramel and enjoy them after a few seconds of cooling.*If you don't have a kitchen torch, you can also broil the crème brûlées on the top rack of the oven at minimally 450°F until the tops are caramelized. Check every 20-30 seconds because sugar can burn very fast.*