Place a wok on high heat and add 1/2 cup of cooking oil.
In a bowl, whisk the eggs, fish sauce, oyster meat, and spring onion.
When the oil just starts to smoke, turn the heat to low and pour in the mixture. It’ll fluff.
Using a spatula, spread the oysters out a bit then lift the edges to get the liquid part of the eggs onto the pan.
When the bottom browns and becomes firm, flip the omelet over and move the loose oysters onto the omelet.
Once the bottom browns nicely, flip once again.
Slide onto a plate and serve.