Gather your ingredients, including eggs, vegetables of your choice (such as bell peppers, onions, tomatoes, spinach, mushrooms, or zucchini), cheese (optional), salt, pepper, and any additional herbs or spices you like (such as parsley or thyme).
Carefully separate the lettuce leaves, rinse them under cold water, and pat them dry with paper towels. Set aside on a serving platter or plate.
In a mixing bowl, crack the eggs and beat them lightly with a fork or whisk until well combined. Season the beaten eggs with a pinch of salt and pepper to taste.
Heat a tablespoon of oil or butter in a non-stick skillet over medium heat. Add the chopped vegetables to the skillet and sauté them until they are tender and slightly caramelized, about 5-7 minutes.
Once the vegetables are cooked, spread them out evenly in the skillet. Pour the beaten eggs over the vegetables, making sure they cover the entire surface of the skillet.
Allow the omelette to cook undisturbed for a few minutes, until the edges start to set and the bottom is lightly golden brown. Use a spatula to gently lift the edges of the omelette and tilt the skillet to let any uncooked egg flow to the edges.
If using cheese, sprinkle grated cheese over one half of the omelette while the top is still slightly runny. This allows the cheese to melt evenly.
Once the bottom of the omelette is set and the cheese is melted, use a spatula to fold one half of the omelette over the other, creating a half-moon shape. Slide the omelette onto a plate and garnish with fresh herbs if desired. Serve hot and enjoy!