Vietnamese and Thai coffees are both made by combining strong brewed coffee with sweet condensed milk. Thai grocery stores sell a ground-coffee mix that contains herbs and chicory. You can brew it as an everyday coffee, with or without the sweetened condensed milk (but that particular type of coffee is delicious sweetened). If you cannot find it, try making this Southeast Asian coffee using espresso. The results will still be delicious. The coffee can be served hot, at room temperature, chilled, or on ice.
Make enough sweet coffee to fill a pitcher by combining 4 parts espresso to 1 or more parts sweetened condensed milk (if too sweet, cut with whole milk). Stir to combine, and refrigerate until well chilled.
To make sweet Vietnamese or Thai tea, brew 1 teaspoon gunpowder tea for every cup of water. Let steep for no more than 5 minutes. Proceed with the recipe, using condensed milk to sweeten each tea drink.