What is a nutritious, filling, and easy to eat breakfast for really early in the morning?

Fil (fermented/soured milk) and musli in my opinion cannot be beaten. Get bowl, open fridge to get fil, pour fil into bowl, get muesli, add that and you are done. Pretty unprocessed, plenty of fiber and (depending on variety) lots of good bacteria. Cleaning up is also quick, water and a few swirls with the brush. Making coffee takes longer than chomping down on a bowl of fil and muesli.