Prepare the tofu marinade by whisking 1 tablespoon cornstarch, oyster sauce, ½ tablespoon water, and white pepper in a bowl until combined. Coat the tofu slices in this marinade.

To cook the tofu, heat a nonstick skillet and add the oil. Pan-fry the tofu slices until golden brown, 1 to 2 minutes per side, then transfer to a plate.

Next, prepare the noodle sauce by mixing the oyster sauce, soy sauce, sugar, and white pepper in a bowl, stirring until the sugar has dissolved.

Place the rice noodles in a large bowl. (If you are using store-bought fresh rice noodles, microwave them for 1 to 2 minutes to soften the strands.)

Add the dark soy sauce to the noodles, rubbing with your fingers so the noodles are evenly coated.

To cook the noodles, heat a large wok and add 1 tablespoon of oil. Add the noodles, spreading them out to cover the bottom of the pan.

Pan-fry for 1 to 2 minutes, not stirring at all, until aromatic and slightly charred. (This step cooks the noodles and also gives them a wok-flavored smokiness.) Transfer noodles to a large plate.

Using the same wok, add the remaining tablespoon of oil, followed by the garlic. Sauté until fragrant.

Add the bean paste and continue to sauté for a few seconds. Add the vegetable stock and bring to a boil. Season with the prepared noodle sauce. Taste and season with salt if needed.

Add the tofu slices to the boiling broth and cook for about 1 minute. (This step allows the tofu to absorb the broth's great flavor.)

Stir the cornstarch with 2 tablespoons of water to make a slurry. Stir this slurry into the boiling broth, then let it keep cooking until the broth turns into a thin gravy.

Add the gai lan and cook for another 45 seconds or so, until the gailan is as crisp-tender as you like.

Ladle this gravy onto the noodles. Serve warm with a side of pickled chiles.