Preheat oven to 450F or 250C/ Gas Mark 8.

Line a large baking sheet with parchment paper.

Separate egg whites and egg yolks.

Place the egg whites in a large bowl and the yolks in a small bowl.

Using a whisk or a hand mixer, beat the egg whites until stiff peaks form.

Gently fold in any added ingredients such as cheese, ham or herbs.

Create 2 mounds of egg whites on the prepared baking sheet.

Indent the centres of each to look like nests.

Bake until slightly golden, about 3 minutes.

Add an egg yolk to the centre of each egg white cloud.

Bake until the yolks are just set, about 3 minutes more.