Prep Your Ingredients: Finely dice your red onion and red pepper, slice the mushrooms, and grate the cheese. Chop your fresh herbs. Having everything ready before you start cooking is key—what chefs call 'mise en place'.

Sauté the Vegetables: Melt half of the butter (1/2 tbsp) in a 20-25cm non-stick frying pan over a medium heat. Add the onion and pepper and cook for 3-4 minutes until they begin to soften. Add the mushrooms and cook for another 4-5 minutes until they are golden and have released their liquid. Season with a small pinch of salt and pepper. Remove the vegetables from the pan and set them aside on a plate.

Whisk the Eggs: In a mixing bowl, crack the 4 eggs. Add the whole milk, chopped chives (reserving a few for garnish), salt, and pepper. Whisk with a fork or a balloon whisk for about 30-45 seconds, just until the yolks and whites are combined and the mixture is slightly frothy. What works best for me is to avoid over-whisking, as it can make the eggs tough.

Cook the Omelette: Wipe the pan clean with a paper towel. Return it to a medium-low heat and add the remaining butter. Once it's melted and sizzling gently, pour in the egg mixture. Let it cook undisturbed for about 30 seconds.

Set the Eggs: Using a heatproof spatula, gently push the cooked edges of the egg towards the centre of the pan, tilting the pan so the uncooked egg runs underneath. Continue this for about 1-2 minutes until the omelette is mostly set but still slightly soft and wet on top.

Add the Fillings: Spoon the cooked vegetable mixture over one half of the omelette. Sprinkle the grated cheddar cheese evenly over the vegetables.

Fold and Serve: Cook for another minute until the cheese begins to melt. Carefully, using your spatula, fold the empty half of the omelette over the filled half. Let it sit in the pan for 30 seconds more to ensure the cheese is gloriously melty inside.

Plate Up: Gently slide the omelette from the pan onto a warm plate. Garnish with the remaining fresh chives and an extra grind of black pepper. Serve immediately.