Mise en Place (Prep): This dish cooks in 3 minutes, so do this first. In a small bowl (Sauce Bowl), combine the light soy sauce, oyster sauce, sugar, and 1 tbsp of water. Stir and set by the stove. In a second small bowl (Slurry Bowl), combine the potato starch (or cornstarch) and 1/4 cup of cold water. Stir well and set by the stove. Wash the lettuce, cut off the root end, and separate the leaves. Mince the 5 cloves of garlic.
Blanch the Lettuce: Bring a medium pot of water to a rolling boil. Add the 1/2 tsp salt and 1/2 tsp cooking oil to the water. Add the lettuce leaves and push them down to submerge. Blanch for only 20-30 seconds. The leaves should turn bright green and just begin to wilt. Do not overcook.
Quickly remove the lettuce with a spider strainer, draining off as much water as you can. Arrange the lettuce on your serving plate.
Make the Sauce: Place a wok or small skillet over LOW heat. Add 1 tbsp of cooking oil and the minced garlic. Stir the garlic for 30-60 seconds until fragrant. Do not let it brown.
Turn the heat to medium-high. Pour in the prepared Sauce Bowl (soy-oyster mixture). Bring it to a boil, stirring constantly (about 30 seconds).
Thicken and Serve: Give your Slurry Bowl a final, vigorous stir to recombine the starch and water. While stirring the simmering sauce in the pan, slowly pour in the slurry. The sauce will thicken and become glossy almost instantly.
If the sauce is too thick, add a splash of water. If too thin, let it bubble for 15 seconds more. Turn off the heat. Stir in the few drops of sesame oil.
Pour the hot, glossy sauce evenly over the blanched lettuce on the plate. Serve immediately.
Serve