Soak fresh eggs in lukewarm water for a few minutes and heat your oven to 105°C/220°F. Lay the eggs directly on the grate and bake for 5 hours. That's exactly 300 minutes.

I just replaced my 18-year-old oven with a digital model that lets you type in the exact temperature and time but I think you could do it with an old oven on the lowest setting, or use an oven proof dish filled with water to cap the temperature around 100°C/212°F.

Remove the eggs from the oven and leave them for 5 minutes in a cold water bowl.

Remove the shell. The egg white has turned brown.

A rather unusual contrast!