Rinse the rice briefly until the water runs mostly clear (removes excess surface starch) then combine the rice and 2 1/4 cups (540 ml) water in a saucepan with a pinch of salt. Bring to a vigorous simmer uncovered, reduce to the lowest heat, cover tightly and cook for 12–15 minutes until the water is absorbed. Turn off heat, let sit covered for 10 minutes. Fluff with a fork and spread on a tray to cool slightly — using mostly cooled rice for wok-frying prevents clumping and gives a better texture.

Slice both proteins thinly against the grain into bite-sized strips (about 1/4-inch thick). Cutting against the grain shortens the muscle fibers and gives a more tender bite.

Marinate the proteins separately: in a bowl for the chicken combine 2 tsp soy sauce, 1/2 tbsp cornstarch (from the 1 tbsp), and a pinch of black pepper. For the beef use 2 tsp soy sauce, 1/2 tbsp cornstarch, and a pinch of black pepper. The small amount of cornstarch and soy helps 'velvet' the surface—when seared it creates a silky coating that locks in juices and helps sauce cling.

Prep the vegetables: slice the onions into 1/2-inch wedges, core and slice the bell peppers into 1/2-inch strips, and mince/slice the garlic. Having everything prepped and within reach (mise en place) is crucial for a fast, high-heat stir-fry.

Make the stir-fry sauce: whisk together the remaining 3 tbsp soy sauce, 1 tbsp brown sugar, the remaining 1/2 tbsp cornstarch, and 1/2 cup (120 ml) chicken stock or water until smooth. This mixture will thicken quickly when added to the hot pan; dissolving the cornstarch first prevents lumps.

Heat a large wok or heavy skillet over high heat until very hot (this shortens cooking time and allows good browning). Add 2 tbsp neutral oil, swirl to coat. When the oil is shimmering, add the beef in a single layer; do not crowd the pan. Let it sear untouched for 45–60 seconds to develop a brown crust (Maillard reaction) which builds flavor, then toss and remove to a resting plate. High heat and quick searing produce color without overcooking the interior.

Return the wok to high heat, add another 1 tbsp neutral oil, then add the marinated chicken in a single layer. Sear until just cooked through and lightly browned (about 2–3 minutes), then remove with the beef. Cook the proteins in separate batches so each piece gets proper sear and doesn't steam.

Reduce heat to medium-high, add a touch more oil if the pan is dry, then add the sliced onions and toss for 2 minutes. Add the bell peppers and continue to stir-fry until the vegetables are bright and crisp-tender (2–3 minutes). Cooking vegetables quickly over high heat keeps them vivid in color and preserves a slight crunch — essential texture contrast against the soft rice and tender meat.

Push the vegetables to the side, add the garlic to the hot spot of the wok for 20–30 seconds to bloom its flavor — garlic burns fast so give it only brief contact with the hottest oil. Then return the beef and chicken to the wok and toss to combine with the vegetables.

Give the prepared sauce a quick stir (cornstarch can settle) then pour it into the wok. Toss constantly until the sauce thickens and coats the meats and vegetables — the cornstarch will reach full thickening power within 30–60 seconds on high heat. Finish with 1 tsp toasted sesame oil for aroma and a final grind of black pepper.

Make the garlic wok-fried rice while the proteins rest if you want to save time: heat 1 tbsp neutral oil in a medium nonstick skillet over medium-high heat. Add half the sliced garlic and toast until pale-golden (20–30 seconds) to flavor the oil, then add the cooled cooked rice. Press and toss the rice so individual grains contact the hot surface — this creates slight crispiness and prevents a gummy pile. Season with 1 tsp soy sauce and adjust salt to taste. Stir in sliced scallions at the end. Using cooled rice and a hot pan ensures fluffy, separated grains.

Serve the stir-fry over a bed of garlic-fried rice, garnish with the remaining sliced scallions and sesame seeds. Let diners mix at the table so they enjoy the contrast of glossy sauce and crisp rice texture.