Preheat your oven to 230 C. Lightly grease a baking sheet using butter.

Crack the eggs into a bowl and separate the yolks from the white (use a empty water bottle for this) and place the yolks in separate small bowls. Pour the whites into the chilled metal bowl and whisk the whites until stiff peaks form. Mix in whatever you want, think chopped cooked bacon, chopped spring onions, shredded cheese, etc.

Spoon the whites into even piles on a baking sheet and create a well in the center of each pile with the back of the spoon. Using 2 eggs, make 2 piles, if making 4 eggs, 4 piles. Bake in the oven for 3 minutes.

Remove baking sheet, add a yolk into each well, bake another 3 minutes. Serve.