Why This Recipe Works
- Making the garlic crisps and using the garlic-infused oil for the stir-fry adds aromatic savoriness to the dish.
- Starting the stems in the hot pan before adding the leaves yields evenly-cooked, tender-crisp greens.
No Vietnamese meal would be complete without a plate of greens, and often, it’s rau muống xào (sautéed morning glory) you’ll see on the table. There are many variations, but the most common is with garlic, which can stand alone as the most basic flavoring, or act as a foundational note to support other flavorings and add-ins. One of my favorite ways to add some heft to this simple dish is to toss in a little bit of beef to make rau muống xào thịt bò (sautéed morning glory with beef).
Affordable and versatile, morning glory (rau muống) is a prized vegetable both inside and outside of Vietnam. It goes by kangkong in Singapore and the Philippines, and kangkung in Malaysia. In North America, it’s commonly known as ong choy (its Cantonese name), as well as water or river spinach (despite bearing no relations to the spinach family—indeed, it is the stems of the morning glory flower that is grown as a popular ornamental plant). This vining aquatic plant with hollow stems and slender pointed leaves is cultivated widely and can grow at a rapid speed of four inches a day.
Its mild vegetal note, tender leaves, and crisp stems make it a perfect candidate for stir-frying, as it readily takes on the flavors it’s cooked with, whether it's fermented shrimp paste, sambal, or oyster sauce. Besides stir-frying, it can be boiled (its cooking liquid repurposed into a soup), slipped into a salad, or pickled. The raw stems can be shredded into fine threads to garnish noodles and hot pots. In folkloric poems, a bowl of morning glory soup evokes nostalgia and homesickness.
My version of rau muống xào thịt bò starts with making the crispy garlic sprinkles that top the dish, an innovation I learned from the Oakland-based chef Tu David Phu. Then I use the garlic-infused oil to quickly sear the beef and set it aside before continuing with the greens.
There are a couple possible ways to go about this stir-fry. Some recipes call for blanching the greens (stems and leaves) and then shocking them in an ice bath before stir-frying. This approach has the advantages of pre-wilting the morning glory for quicker stir-frying later and locking in its vibrant green color. The other is to give the thicker stems a kick-start in the hot pan, given their slightly longer cooking time, then adding the more delicate leaves.
Testing both methods side-by-side, my husband and I preferred the two-stage cooking process, which started with stir-frying the stems in half of the sauce (a mixture of soy sauce, oyster sauce, and water) until they softened slightly, followed by the leaves and the remaining sauce. Compared to the blanched batch, this yielded more flavorful greens and retained the contrasting texture of crunchy stems with tender leaves—not to mention that no additional pot or colander was needed, a definite bonus. As with other stir-fries, the key is to get all of your ingredients ready and within reach before cooking, and work quickly once cooking has started.
Normally, a vegetable stir-fry is part of a meal with multiple dishes, and its more reserved flavor profile makes it a good counterpart to more boldly flavored dishes on the table, but with the added beef and served with some steamed rice, this is substantial enough on its own.
Rau Muống Xào Thịt Bò (Vietnamese Sautéed Morning Glory With Beef)
Tender-crisp greens go from aromatic side to main course with the addition of beef.
- For the Beef:
- 1 tablespoon (15ml) oyster sauce, such as Panda brand
- 1 tablespoon (15ml) soy sauce (see note)
- 1 teaspoon (4g) sugar
- 1 teaspoon (5ml) neutral oil, such as vegetable or canola oil
- Freshly ground black pepper
- 1/2 pound (227g) flank steak, sliced against the grain into 2-inch-long and 1/8-inch-thick strips
- For the Stir-Fry:
- 2 tablespoons (30ml) oyster sauce, such as Panda brand
- 1 tablespoon (15ml) soy sauce, plus more if desired
- 1 tablespoon (15ml) water
- 3 tablespoons (45ml) neutral oil, such as vegetable or canola
- 4 medium cloves (28g) garlic, finely chopped
- 1 bunch morning glory (1 to 1 1/2 pounds; 450g to 680g), stems and leaves separated, stems cut into 3-inch segments
- Freshly ground black pepper
- Steamed jasmine rice, for serving
For the Beef: In a medium bowl, whisk together oyster sauce, soy sauce, sugar, oil, and freshly ground black pepper. Add beef, tossing to coat, and let marinate for 30 minutes.
For the Stir-Fry: In a small bowl, combine oyster sauce, soy sauce, and water. Set stir-fry sauce aside.
In a large stainless-steel skillet or wok, heat oil on medium heat until shimmering. Add garlic and cook, stirring occasionally, until golden, 2 to 3 minutes. Scrape garlic and oil into a fine-mesh strainer set over a heatproof bowl. Set garlic aside, then return 1 tablespoon (15ml) garlic oil to skillet (reserve any remaining garlic oil for another use, or discard).
Return skillet to high heat and heat until oil is shimmering. Add beef and its marinade in a single, even layer. Let cook, undisturbed, for 30 seconds; then, using a metal spatula, stir while continuing to cook until beef turns mostly gray with a few pink spots, 30 seconds longer. Transfer beef to a medium bowl.
Add reserved garlic oil to same skillet. Set over high heat, then add morning glory stems and half of stir-fry sauce. Cook until stems soften slightly, about 1 minute. Add morning glory leaves and remaining sauce and cook, stirring and tossing, until leaves wilt and lose half of their original volume, 2 to 3 minutes. Add beef and any accumulated juices and cook, stirring and tossing, until last traces of pink disappear and sauce coats vegetable and beef, about 1 minute.
Transfer sautéed morning glory and beef to a serving dish. Season with additional black pepper and soy sauce, if desired, then top with fried garlic and serve immediately with rice.
Morning glory can be found in Asian grocery stores under different names: rau muống, ong choy, water spinach, kangkong. When shopping for these greens, choose bunches with perky leaves and uniformly thin stems that snap easily. Older ones have larger stems, which can be tough and fibrous.
I've made this recipe with Vietnamese and Chinese soy sauces, and both work—the quantity used is small enough not to make a huge difference on the finished dish regardless of origin.
You can omit the beef entirely and make this a meatless dish.