Steep coffee grounds in a heatproof container with 2/3 cup boiling water for 4 minutes. Pour through a coffee filter into a heatproof glass.

Alternatively use a metal filter.

Bring 1 cup water to a boil. Remove the top screen from the filter, add coffee, then screw on the top screen. Place filter over a heatproof glass or measuring cup.

Pour a splash of the hot water into the filter; this will allow the coffee grounds to bloom. When coffee begins to drip through, add enough water to reach the top of the filter. Place lid on the filter and let the coffee drip for 4 minutes. If coffee stops dripping sooner, gently loosen the screw to relieve pressure.

Stir in condensed milk until blended. Add ice, stir, and serve.