Prep the Base: Pour 1–2 tbsp of condensed milk into your serving glass.
Brew the Coffee: Set up your Phin filter with the coffee grounds. Use the Double-Bloom method: add 1 tbsp of hot water to the overturned lid and 2 tbsp to the top of the chamber. Wait 2–3 minutes, then fill the chamber with hot water and let it drip completely into the glass with the condensed milk.
Whip the Salted Cream: In a separate small glass or pitcher, combine the cold heavy cream, 1 tbsp condensed milk, and the sea salt.
The Froth: Use your handheld frother for about 30–60 seconds. Stop when the cream has thickened into a "pourable velvet" consistency—it should be thicker than milk but still fluid enough to pour.
Assemble: Stir the brewed coffee and the condensed milk base together until smooth. Gently pour or spoon the cold salted cream over the top. It should sit on the surface and slowly begin to marble down into the dark coffee.