Preheat the oven to 180°C.
In a bowl, with an electric beater the eggs whites until stiff peaks form.
Line a baking tray with baking paper. Place the bread on the baking tray.
Spoon a mound of egg white onto each slice, then make a little crevice on the very top and gently place the egg yolk in it.
Sprinkle with Parmesan and a grind of black pepper (the volcanic ash).
Bake until the egg white is firm, the cheese melted, and the egg yolk runny when you cut into it (molten lava), 8 to 12 minutes.