Vietnamese egg coffee recipe: Hanoi's 1946 classic

Cà phê trứng, Vietnamese egg coffee, tops hot robusta with a whipped egg yolk and condensed milk foam, a Hanoi fix invented in 1946 when fresh milk ran short. This is Amuse Kitchen's version of the recipe, close to the original and tied to the dish's current moment: Philadelphia's Cáphê Roasters, which is doubling in size next spring, serves it alongside matcha drinks and bánh mì.

Nguyễn Văn Giảng created the drink at Café Giảng in Hanoi during a dairy shortage, whisking egg yolks with sugar and condensed milk into a foam that could carry coffee's bitterness without fresh milk. His family still runs the café today, and the recipe has since travelled with the Vietnamese diaspora to roasters tracked on lists like the Podium Index.

The technique, not a long ingredient list, makes the drink work: whisking air into egg yolk and condensed milk until it holds its shape, then pouring hot coffee underneath rather than through it, so the foam floats instead of collapsing.

The foam is the whole dish: whisk until it holds its own weight.

Ingredients

• 2 egg yolks, at room temperature
• 3 tablespoons sweetened condensed milk
• 1 pinch of salt
• 60 ml strong robusta coffee, brewed hot (phin filter or moka pot)
• Ground cinnamon or cocoa powder, to finish

Method

1. Brew the coffee first and keep it hot; the foam needs real heat underneath to stay warm through serving, so timing the coffee to finish last works better than waiting on the yolks.
2. Separate the yolks carefully, keeping out every trace of white, which stops the foam from whipping to a stable peak.
3. Whisk the yolks, condensed milk and salt together, by hand or with an electric whisk, for 7 to 10 minutes, until the mixture triples in volume and holds a ribbon when the whisk lifts away.
4. Pour the hot coffee into a small glass or cup, filling it about two-thirds full.
5. Spoon the whipped yolk foam gently on top so it sits as a distinct layer rather than mixing into the coffee; the foam's structure, not the glass, keeps the two apart.
6. Dust with cinnamon or cocoa and serve immediately, with a small spoon so the foam can be eaten in part before it is stirred through.

Serve it hot, or let it turn into dessert

Café Giảng serves cà phê trứng hot, in a bowl of hot water that keeps the glass warm at the table; an iced version, cà phê trứng đá, chills the coffee first and sets the foam on top of ice, closer to a drink than a dessert. Either way, the foam holds best in the first ten minutes, so this is a drink to make for one sitting rather than a batch to hold.

Cooks wary of raw egg can use pasteurised egg yolks, sold in cartons in most supermarkets, without changing the method or the whisking time.

Can I whip the foam by hand? Yes, with a balloon whisk and about 10 minutes of steady work; an electric whisk just gets there faster.