I have a similar go to for the kids, though typically just do more of a pancake style in a small pan to keep it a little thicker.
- eggs
- Diced onion (or dried onion flakes?) if feeling lazy
- medium fine chop of a leafy greens mix (spinach, kale, ?)
- shredded cheese
- a sort of generic seasoning mix
- add other protein/vege that’s on hand
I also have little round silicon molds that are the perfect size to fit in a little sandwich; add a bit more cheese to the bread, add the egg, throw it in the toaster oven.