Pre-heat oven to 200°C/390°F (180°C fan).

First, separate eggs and place whites in a bowl. Reserve yolks for another use.

Cook asparagus and prosciutto: Heat olive oil in a 20cm/8" oven-proof, non-stick pan over medium heat. Add asparagus and cook until tender. When almost done, add prosciutto and stir for 30 seconds – just enough to warm through but not crisp. Transfer to a bowl and set aside.

Melt butter: Add butter into the same skillet and place over low heat. The butter should melt and be bubbling gently (ie. hot, but not smoking) when the egg whites are ready to pour in. (Note 3)

Whisk whites until it's just opaque, fluffy and creamy. Do not take it to "stiff peaks". It should be a consistency so you can draw a figure 8 on the surface and it stays there without sinking. You do not want to be able to do "elf hats" (see in post for photo), that's too stiff. (Whisking time for me: 90 seconds by hand, 30 seconds on Speed 4 electric beater).

Add chives, salt and pepper. Whisk a few times just to mix through.

Immediately pour egg whites into hot skillet, spread with a spatula to cover surface. Stir for 10 to 12 seconds until the whites start to set on the base.

Remove from stove, then lightly tap the pan 5 times on the stove grates or a heat mat to remove bubbles from the base.

Sprinkle asparagus, prosciutto and pecorino on half the omelette (the half opposite the handle).

Transfer to oven for 2 minutes.

Remove from oven. Run rubber spatula around edges and then under the side without the filling, carefully fold omelette in half to cover the filling.

Press the omelette's rounded edge against the side of the pan for 30 seconds to seal the edge.

Turn out onto plate: Hold a plate at a 45 degree angle. Then flip the omelette out onto the plate so it lands upside down, ie. pan-contact face up (see video for demo).

Garnish with chives. Serve immediately!