Add the heavy cream and Thai tea mix to a saucepan, stir, and steep the tea on low for about 5-7 minutes until warm. Continue stirring occasionally.
Separate 4 eggs, reserving the whites for another time.
Preheat the oven to 325℉ and add the empty ramekins to a 13x9” casserole dish.
Strain the cream through a fine mesh strainer into a bowl to remove the large pieces of tea, then rinse out the pot to remove all pieces.
Strain the cream again through the smallest mesh strainer you have (I recommend using cheese cloth, as well) into a 2 cup liquid measuring cup. Some very tiny specks will remain.
Use the additional cream to bring the amount of cream back to 2 cups (475g). Transfer the cream to the rinsed pot and add the sugar and salt. Heat over medium heat, stirring occasionally, until the sugar dissolves and it comes to a simmer.
During this time, vigorously whisk the egg yolks in a medium sized bowl for about 1 minute. The mixture will become a bit lighter in color and slightly airy.
Once the cream comes to a simmer, drizzle in one ladle full of cream to the egg mixture while whisking. Do the same with a second ladle, then transfer the egg mixture into the pot with the cream. Whisk immediately until combined. Ladle the mixture evenly between the ramekins.
Boil a small pot of water and pour it into the pan in between the ramekins. Fill the pan halfway with water.
Transfer the pan to the preheated oven and bake for 20-25 minutes. The custard will still feel rather sloshy and jiggly, but will be slightly set on the edges.
Remove from the oven, and very carefully transfer the ramekins to a wire rack to cool using tongs and a dish towel. Keeping them in the water will cause the custard to overcook. Cool for 30 minutes, then transfer to the fridge for at least 4 hours, or overnight (uncovered).
When ready to serve, add a spoonful of sugar to the top of one ramekin, rotate the ramekin to spread evenly, then dump the excess sugar to the next ramekin and repeat. Use a kitchen torch to brûlée the sugar until caramelized. Then, sprinkle on a thin layer of sugar with your fingers and brûlée again. This double method creates the best crust and crack.