Thanks, I will have a fridge and hadn’t thought about that. Will probably take some berries and a small yoghurt pot in a cool bag. Some nuts would be good for mid morning as well.
You could easily take hard boiled eggs, cooked bacon, cooked sausages if you really need to identify with the breakfast you are eating as a breakfast. If you're a bit more relaxed about it being strictly classic breakfast fare, the cooked chicken or any cold meats are easy.
If you're concerned about freshness or the availability of the fridge, lots of those ^^^^ things could be frozen when leaving home, with a long defrost. I guess that depends on how long your home > airport journey is and whether a cool back would be workable for the trip or whether that would mean you'd have to take a cool bag on holiday with you.
I've done exactly the scenario you describe many, many times.
Alternatively if the terminal building your go to/from has an M&S Food store then they sell protein post, lots of cooked meats including their crispy bacon strips, Greek yoghurt, small tubs of fruit, individual portions of cheese you could buy when you get there in the morning.
If you are going transat and using twilight check-in you could buy from M&S after you have checked in. If twilight check-in is available and you haven't tried it before I wholeheartedly recommend it. Just arriving directly to Departures security in the morning, fresh and unfettered by luggage works for me.
Did I mention I'd played this game a gazillion times for early outbound and even earlier picking up my OH, from his transat?
