Crack the eggs into a bowl and whisk until fully blended.
Season with salt and pepper to taste.
Heat a non-stick skillet over medium heat and add the butter.
Once the butter is melted and bubbling, pour in the eggs.
Tilt the pan to spread the eggs evenly.
Cook for 1-2 minutes until the edges start to set.
Add the diced vegetables and cheese on one half of the omelette.
Carefully fold the other half over the filling using a spatula.
Cook for an additional 1-2 minutes until the cheese melts.
Slide the omelette onto a plate and garnish with fresh herbs if desired.