Sauté the mushrooms: Heat the olive oil in a large non-stick frying pan over medium-high heat. Add the sliced mushrooms and cook for 3–4 minutes, stirring occasionally, until they release their moisture and turn a deep, golden brown. You’ll hear a gentle sizzle at first, then a quieter hiss as the water evaporates. The mushrooms should look glossy and smell deeply savoury.

Add the garlic and herbs: Reduce the heat to medium, add the minced garlic, and cook for 30 seconds until fragrant — your kitchen will suddenly smell wonderfully aromatic. Stir in half the chopped chives and parsley, then remove the mushroom mixture from the pan and set it aside.

Whisk the eggs: Crack the eggs into a mixing bowl, add a splash of milk if using, and season with salt and pepper. Whisk vigorously for about 30 seconds until the mixture is pale yellow, frothy on top, and completely uniform. You’re looking for a smooth, single-colour liquid with tiny bubbles across the surface.

Melt the butter: Wipe the pan clean with kitchen paper, then return it to medium heat. Add the butter and let it melt slowly, tilting the pan to coat the base. When the butter stops foaming and smells nutty, you’re ready to pour in the eggs.

Cook the omelet base: Pour the whisked eggs into the centre of the pan. Let them sit undisturbed for 20 seconds until the edges start to set and turn a pale, opaque yellow. Using a spatula, gently push the cooked edges toward the centre while tilting the pan to let the uncooked egg run to the edges. Repeat this once or twice until the top is still slightly wet and custard-like.

Add the filling: Spoon the cooked mushrooms evenly over one half of the omelet. Sprinkle the grated cheddar cheese on top, followed by the remaining fresh herbs. The cheese should look like a golden blanket over the mushrooms.

Fold and finish: Using your spatula, carefully fold the empty half of the omelet over the filling. Let it cook for another 30–40 seconds until the cheese is melted and the bottom is a light golden brown — you’ll see a few brown spots on the surface. Slide the omelet onto a plate and serve immediately, or set aside to cool for batch storage.