- Break eggs into a bowl, add water and parsley, then whisk to combine. Season with salt and pepper.
- Heat butter or olive oil in a nonstick frying pan over a medium heat until the butter sizzles. Pour in the egg mixture. Draw the mixture away from the sides of the pan towards the centre as it cooks.
- When the egg mixture is nearly cooked, add the filling ingredients to one side of the omelette.
- Flip the unfilled side of the omelette over onto the filled side, then gently slide the omelette onto a plate to serve.