Start by gathering all your filling ingredients – diced cooked chicken (or any leftover meat you prefer), chopped mushrooms, green onions, and bean sprouts. You can also add other vegetables like bell peppers, shredded carrots, or bamboo shoots to add more variety and color to the omelette.

In a mixing bowl, crack four large eggs. Whisk them until the yolks and whites are well combined. To add an authentic Chinese touch to the omelette, you can beat the eggs using chopsticks instead of a whisk.

Now, it's time to infuse the eggs with Chinese flavors. Add soy sauce, oyster sauce, sesame oil, Shaoxing wine, sugar, and white pepper to the beaten eggs. These seasonings will give your omelette a umami-rich taste that sets it apart from a regular omelette.

Combine the diced chicken, chopped mushrooms, green onions, and bean sprouts with the seasoned egg mixture. Make sure all the filling ingredients are evenly distributed in the eggs.

Place a non-stick frying pan over medium heat. Add the vegetable oil and allow it to heat up. You can swirl the oil around the pan to ensure it coats the entire surface.

Once the pan is adequately heated, pour the egg mixture into the pan. Use a spatula to spread the filling evenly and shape the omelette if needed. Let the omelette cook undisturbed for a couple of minutes until the edges start to set.

To enhance the taste and texture of your Chinese omelette, add a tablespoon of butter on top. As the butter melts, it will infuse the omelette with a rich, nutty flavor.

Once the edges of the omelette have set and the bottom is golden brown, it's time to flip it. Be cautious while flipping to avoid spilling the filling. You can use a large flat plate or another pan to carefully turn the omelette over. Cook the other side for a few minutes until it turns golden brown and the omelette is fully cooked.

To ensure that your omelette is thoroughly cooked, insert a knife into the center. If it comes out clean without any runny egg, then your Chinese omelette is ready!

Remove the omelette from the pan and transfer it to a serving plate. Garnish with fresh cilantro for an extra burst of flavor and a pop of color. Slice the omelette into wedges and serve it hot.