Wash the baby corn and cut it diagonally into chunks (roll-cut), so each piece has more surface to catch flavor. Trim the roots off the black oyster mushrooms and tear them by hand into bite-size strips. Cut the tomatoes into irregular chunks — they are part of the seasoning here. Rinse the button mushrooms, wipe off any wood shavings, and slice them thick. Wash right before cooking so they don't soak up water and go soft.

Heat a wok over medium-high and add a thin even layer of oil. Add all the mushrooms — button slices and black oyster strips — and stir-fry. Let them sit just long enough to develop a golden-brown, lightly caramelized edge. This toasty "wok hei"-adjacent sear is the flavor anchor of the whole dish. Keep turning until the mushrooms are golden and fragrant.

Drop in the tomatoes and baby corn and toss everything together over high heat. Stir quickly so the tomatoes begin to release their juice but the corn stays crisp.

Season with 1 tsp salt and 1/4 tsp white pepper. Add a pinch of oregano (to taste) — it pairs beautifully with the earthy mushrooms. If you prefer a sweeter finish, stir in 1/2 tsp sugar; the tomatoes already bring natural acidity.

Splash 1 tbsp of water around the edge of the wok and toss to combine. Let it simmer (煨煮) briefly until the tomatoes soften and the liquid reduces into a shiny, glossy glaze. Stop when everything is coated and the sauce has just absorbed — the tomatoes soft, the corn still crisp. Pile onto a plate and serve hot over steamed rice.