I do not serve "left overs", there was a very negative comment from a parent few years ago insinuating that homedaycares serve only left over which wasn't the service they were paying for.

I do my meals from scratch every day around 6 am. And my family has the left overs of our lunch time.

If you search how restaurants and chefs handle properly food you will get lots of tips to prepare things way ahead. Ex. Salads, soup mixes, crock pot recipes already mixed freeze and cook it etc. Search pinterest you'll get absolutely many ideas. You'll find your own system the way it works best for you. Spring and summer we set a lot more raw veggies so I focus a lot on those months to introduce new foods too. Fall and winter mostly crock pot meals, all year round frunits are always easy to offer. My kids learned to eat every thing cooked or raw veggies.