As you come in for a landing at the Guangzhou airport, the city passes by your window practically forever. In the dusky late afternoon, the colors are drained from endless rows of cookie-­cutter buildings. The sheer size and mass overwhelms. How was I to know, in this city of over 13 million, that when locals feel lonely, they go home and whip up a stir-fry of eggs and tomatoes? (Or better yet, have their mothers make it.)

Eggs are a comfort food the world over, as evidenced in life and in film. In “The Deer Hunter,” a breakfast of eggs and “God Bless America” serves as a tearful tribute to the fallen Nick. In “Big Night,” in the early-­morning hours after the famed Louis Prima fails to show at the restaurant, eggs are whisked, and the brothers share an omelet (with a third plate for the waiter); they place their arms around one another’s shoulders.

In China, it’s no different. From Shanghai to Chengdu, stir-fried eggs and tomatoes are served in diners and cafeterias, from food stalls on the street, on dinner tables, even lukewarm in lunch boxes. It’s the equivalent of spaghetti and tomato sauce, a meal made almost intuitively, with hardly a need for a recipe.

Lightly beaten eggs are swirled in a hot wok, quickly shuffled around in the heat until just set, then taken out and set aside. Next come the fresh tomatoes, usually sliced into wedges. They’re tossed in the wok, then cooked until they release their juices and soften. 

The last step—what you use (and how much) to flavor the tomatoes and their juices—is what gives rise to the multitude of mothers’ variations. You might include ketchup, sugar, cornstarch or potato flour, Shaoxing rice wine, scallions, ginger, white pepper or sesame oil.

Finally, the eggs are tossed together with the tomatoes and the sauce, spooned onto a platter and served. The dish is mostly savory, a touch sweet and overwhelmingly simple and satisfying.

The core problem at Milk Street was adapting the recipe to a skillet. A wok is ideally suited for egg cookery—the center of the pan gets very hot and the eggs can be swirled about in seconds, achieving the proper fluffy texture. But many domestic burners don’t have enough heat output for a wok, and most American cooks don’t own a wok.

Using a skillet, we let the eggs puff up at the edges before pushing them around in the pan. That got us the right texture, but the dish still didn’t seem unified. The sauce felt superfluous, not essential.

Cooking the tomatoes gave us trouble, too. By the time they released their juices, they were overcooked and mushy. The answer was to separate the tomatoes from the sauce. We gave them an initial toss in rice vinegar and white pepper to boost their flavor, blistered them in the smoking-hot skillet for just under a minute, then added them to our cooked eggs.

That only left the sauce. Since we weren’t cooking the tomatoes until they gave up their juices, we used a base of unseasoned rice vinegar, ketchup and water as a substitute. To that we added ginger, garlic, red pepper flakes and sesame oil, plus soy sauce and white pepper (which we had used to season the eggs).

When we poured it into the hot, empty skillet, just after removing the tomatoes, the sauce  thickened in no time. Poured over the tomatoes and eggs, it was at once foreign and familiar, as comforting in Boston as in Guangzhou.