Crack the eggs into a mixing bowl, then season with a pinch of sea salt and black pepper. Whisk vigorously with a fork until fully combined and slightly frothy.

Place a small frying pan over low heat and melt a knob of butter until it starts to bubble gently. Pour in the beaten eggs, tilting the pan to ensure an even spread. Let the eggs cook undisturbed for a few moments until they start to set around the edges but still have a slightly soft center.

If using cheese, sprinkle it evenly over the omelette while the top remains slightly runny. Using a spatula, carefully loosen the edges, then fold the omelette in half. Cook for another moment until the underside develops a light golden hue. Remove from heat and slide onto a plate, ready to serve.

Tear the basil leaves into small pieces. Slice the cherry tomatoes in half. Heat a small frying pan over medium heat, then melt a knob of butter along with a drizzle of olive oil. Add the tomatoes, season with salt and pepper, and sauté for about a minute, stirring occasionally. Reduce the heat slightly, then scatter the basil leaves over the tomatoes.

Pour in the beaten eggs, tilting the pan to spread them evenly. Allow the omelette to cook as described in the basic method, folding once it begins to set. Transfer to a plate and serve immediately.

Quarter or roughly chop the mushrooms. Heat a small frying pan over medium heat and melt a knob of butter with a drizzle of olive oil. Add the mushrooms and season with salt and pepper. Sauté, stirring frequently, until the mushrooms are golden and tender. Lower the heat slightly before adding the beaten eggs, spreading them evenly across the pan.

Once the omelette starts to firm up, but with a slight softness on top, sprinkle the Cheddar cheese evenly. Follow the same folding and cooking method as the basic omelette, ensuring the underside is lightly golden before serving.