Vietnamese Egg Coffee (Cà Phê Trứng): How to Make Hanoi’s Custard-Topped Coffee

Vietnamese egg coffee — cà phê trứng — is strong coffee topped with egg yolk whisked with sweetened condensed milk into a thick, pale, custard-like foam. To make one, brew a small, strong cup of coffee in a phin, whisk a yolk with two tablespoons of condensed milk for three to five minutes until it is pale and doubled in volume, and spoon the foam over the coffee.

It is Hanoi's most famous coffee, and it eats as much as it drinks: a spoonful of sweet, airy cream on top, bitter coffee underneath.

The recipe

1. Brew the coffee into a small cup. The Vietnamese coffee guide explains how to use a phin; a strong double espresso works too.
2. Keep it warm. Set the cup in a bowl of hot water, as many Hanoi cafés do.
3. Whisk the foam. Beat the yolk, condensed milk and sugar with an electric whisk or a handheld milk frother for three to five minutes, until the mixture turns pale ivory, thick and roughly doubled in volume.
4. Spoon it over the coffee gently, so it sits on top.
5. Serve with a spoon. Eat some of the foam first, then stir the rest in and drink.

Where it came from

Egg coffee has a precise origin. In 1946, at a time when fresh milk was hard to come by, Nguyễn Văn Giảng, a bartender at Hanoi's Metropole hotel, began whisking egg yolk into a sweet, meringue-like foam as a substitute and spooning it over hot coffee. According to his son, Nguyễn Văn Đạo, speaking to Viet Nam News, the original recipe included yolk, condensed milk, coffee, butter, cheese and some secret ingredients.

The drink was popular enough with the Metropole's guests that Giảng left to sell it himself, founding Café Giảng. It is still run by his family — today by his youngest son, Nguyễn Trí Hòa — in a small alley on Nguyễn Hữu Huân Street, and it has added versions with rum, green bean, chocolate, cinnamon and green tea, and even an egg beer.

Why the foam holds

Whisking a yolk with condensed milk turns two thick liquids into a stable, spoonable foam. Two ingredients make that possible.

Egg yolk is an emulsifier. By weight, a yolk is roughly half water, 16% protein, 9% lecithin and 23% other fat. Lecithin and the yolk's proteins gather at the surface of air bubbles and fat droplets and keep them from merging, which is why yolks hold mayonnaise and custards together — and why they can hold air.

Condensed milk thickens it. Sweetened condensed milk is more than half sugar. Dissolved sugar makes the liquid between the bubbles viscous, slowing the drainage that makes foams collapse, so the topping keeps its shape on hot coffee for a long time.

The closest European relative is the Italian zabaglione, egg yolks whipped with sugar and sweet wine into a light custard that holds a large amount of air. Egg coffee's foam is essentially a zabaglione made with condensed milk instead of wine, and eaten on coffee.

Making it safely

The classic topping is made with raw yolk, and raw eggs can carry Salmonella. The risk per egg is small but real: research cited by the US Department of Agriculture estimates that about 1 in 10,000 to 20,000 eggs in the United States is contaminated, and that about a fifth of the population — including pregnant women, infants and young children, older people and people with weakened immune systems — is especially susceptible.

The simple answer is pasteurised eggs, which are gently heat-treated in the shell to destroy most bacteria without cooking the egg. An analysis cited in the same USDA presentation estimated that pasteurising all US eggs would cut egg-related Salmonella illnesses from about 130,000 a year to about 19,000. Use them exactly as you would raw eggs in the recipe — and always when making egg coffee for anyone in the higher-risk groups.

Calories and sugar

Egg coffee is a dessert in a cup. The USDA lists a large egg yolk at about 17 g and 55 kcal, and sweetened condensed milk at 321 kcal and 54 g of sugar per 100 g, so two tablespoons — about 38 g — add roughly 122 kcal and 21 g of sugar. The topping alone therefore comes to about 175 kcal and 21 g of sugar, before the optional teaspoon of sugar, which is nearly all of the 25 g a day of free sugars below which the World Health Organization suggests further health benefits.

The coffee underneath is strong. Vietnamese coffee is usually made largely from robusta, which has roughly twice the caffeine of arabica, and brewed as a small, concentrated cup; the Vietnamese coffee guide explains why it is one of the strongest cups you can order.

Variations

• Iced egg coffee — the coffee goes over ice and the foam on top.
• With cocoa — a dusting of cocoa powder, or patterns drawn in chocolate sauce, as some Hanoi cafés do.
• With rum or other flavours — Café Giảng's menu includes rum, chocolate, cinnamon and green tea versions.

For another coffee with a whipped, sweet topping, see dalgona coffee; for another that uses condensed milk, the Cuban cortadito.