I said sauteed to simplify, but what we do is a kind of ratatouille. We do it once every 2-3 weeks and use a bit on every breakfast. We freeze it in batches, and every couple of days we defrost a new batch in the fridge.
Our version of ratatouille has tomato, eggplant, onion, zucchini, and carrot.
Typically we do scrambled eggs, preheat the ratatouille, and then serve it on top of the eggs with sprinkled goat cheese. It's super easy and fast to do for any number of people.
Another preparation we absolutely love is: a toast of low glycemic Ezekiel bread[1] with the pre heated ratatouille on it, some sprinkled goat cheese, and a fried egg on top of everything with sprinkled hot salsa (I guess some Sriracha would work too if you're into that). It's delicious.
We also typically add half avocado on the side of those dishes. Since we live in Mexico these are plentiful and very cheap.
We've measured our blood glucose before and after eating either of those breakfasts and it barely changes.