Crack the eggs into a bowl. Whisk or beat until light and frothy.
Heat a non-stick frying pan over medium heat and add your butter or oil.
Add the prawns and cook for 2 minutes or until nearly cooked through. Add the tomato and stir once or twice.
Pour in the eggs in the pan and sprinkle the cheese over.
Move the back of a fork or a spatula through them in small circles, allowing the uncooked egg to flow into the gaps for 1 -2 minutes. Stop stirring once the eggs have begun to set but are still very moist in appearance.
Season with salt and pepper.
Remove from the heat and use a spatula to fold the omelette in half or thirds.
Leave to settle for a few seconds, then transfer to a serving plate and serve immediately.