Set up your Vietnamese phin filter on top of your coffee cup and add the 25 grams of coffee grounds. Mix the cocoa powder and one pinch of salt directly into the coffee grounds, ensuring even distribution. Place the filter insert on top and have your hot water ready at the proper temperature.
Begin the brewing process by slowly pouring 40ml of hot water over the coffee mixture, allowing it to saturate evenly. Wait 30 seconds for the coffee to bloom - you'll notice it puff up slightly as gases release. This blooming step is crucial for extracting the full flavor profile. Pour the remaining 60ml of hot water slowly and let it drip through the filter, which should take 4-5 minutes.
While the coffee drips, prepare your salted cream by combining the cold heavy cream, whole milk, sugar, and two pinches of salt in your small mixing bowl. Using your milk frother or whisk, whip the mixture until it forms soft peaks - the cream should hold its shape when lifted but have gentle curves at the tips rather than stiff points.
Pour the sweetened condensed milk into your serving glass first, creating the base layer. Once your coffee finishes dripping, pour it over the condensed milk and stir thoroughly to combine. Add several ice cubes to the glass and give it another gentle stir to cool the coffee mixture.
Carefully spoon the whipped salted cream on top of the iced coffee, allowing it to float and create a distinct white layer. The cream should sit proudly on the surface without immediately sinking. Finish by lightly dusting cocoa powder over the cream using a fine strainer or sieve for an elegant presentation.
Allow the drink to settle for a moment before serving. You can either stir the cream into the coffee as you drink or sip through the cream layer - both methods offer delicious but different flavor experiences with each sip.