Yum I could live on Nutella. Some nice Rye bread and some Nutella equals bliss. But I would never serve Nutella in the daycare.
I make lunch and snacks the same for everyone. Usually snacks are more successful than lunches. I also have a 3 yr old who can be quite picky.
She will look at the lunch like lasagna or pasta and say "My tummy is full". I then ask her to take 3 bites and then she can be excused.
She is good about the 3 bites and then leaves.
It often happens that she then says during quiet time that she is hungry. I just look her in the eyes and smile politely and say "I am sure you are because you didn't eat all of your yummy lunch but now you will have to wait until the babies wake up and we have snack."

I know she likes rice and chicken with corn so I try to make that on at least one day when she is here...or soup.

I do a treat day every 3 weeks or so where we have Ravioli or Grilled Cheese or KD and of course I never hear her tummy is full those days but I don't make a big deal about it. I ask her to at least try foods (the 3 bites) and then she can either choose to have more or wait for snack.