Heat a large non-stick frying pan over high heat, greased with a little bit of oil. Slice the mushrooms and cook, stirring occasionally, for 5-7 minutes. Transfer to a bowl and set aside
Heat a small non-stick frying pan over medium-high heat, greased with a small amount of oil. Whisk the eggs in a large pot with ¼ cup (60ml) cold water. Season well with salt and pepper.
Pour quarter of the eggs into the pan and cook the omelette. Top with a quarter of the earlier prepared mushrooms and quarter of the brie. Transfer onto a serving plate, top with a handful of rocket. Serve immediately.
Repeat this process with the remaining eggs, mushrooms, brie and rocket to make a further 4 omelettes.