20 g (3 tbsp) Vietnamese dark-roast coffee (robusta or a robusta blend), ground medium-coarse
100 ml (scant 1/2 cup) boiling water
2 tbsp sweetened condensed milk
A Vietnamese phin filter, and a glass full of ice
How to make it
Set up (1 min): Spoon the condensed milk into a heatproof glass. Put the phin on top, add the coffee, shake it level and set the press disc on top without pressing.
Bloom (30 sec): Pour in about 20 ml of boiling water to wet the coffee and wait 30 seconds while it swells.
Drip (4 to 5 min): Fill the phin with the rest of the water and put the lid on. It should drip slowly, a drop or two a second. If it pours, the grind is too coarse; if nothing comes, loosen the disc slightly.
Mix (30 sec): Take off the phin, stir the coffee and condensed milk together until caramel coloured.
Ice (10 sec): Pour over a glass full of ice, stir, and drink. For cà phê đen đá, skip the milk and add sugar to taste.
Tips
The slow drip is the whole point: it gives the thick, chocolatey strength robusta is known for.
Try it hot as cà phê sữa nóng: same coffee, no ice, the glass standing in a bowl of hot water.
Trung Nguyên is the brand found in most Asian groceries; a dark French roast stands in fine.