Place a frying pan over a medium heat then add garlic oil spray and heat. Add the peppers, onions and chilli and cook and stir for 2 to 3 minutes.
Add the prawns and cook for another 2 to 3 minutes.
In a second medium-sized frying pan heat the butter spray over a medium heat and pour in the eggs. Tilt the pan gently to spread the egg out over the base of the pan. Cook egg for 3 to 3 minutes then season with pepper.
Remove both pans from the heat and spoon the vegetables and prawns over the egg, and sprinkle over the cheese (at this stage depending on how well you like your egg, you may want to pop it under a grill for a minute or two to cook the top). Check the bottom of the omelette to see the colour and cook more if needed.
Roll omelette from one side to the other. It's a little bit tricky but once you do it a few times it's no problem. Serve immediately.