for Pete Won't Eat by Emily Arnold McCully
Everyone is mad at Pete! Even Mom! But Pete can't eat that green slop that Mom made for lunch. He won't even taste it! His siblings want Pete to eat so they can go out to play. But Pete stands firm, and his siblings desert him. Mom makes Pete stay, but she is feeling sad about it. She is about to make him a sandwich when Pete decides to try the slop. He likes it! In addition to enjoying the yummy slop, Pete has learned the benefits of keeping an open mind and trying new things.
Publisher description retrieved from Google Books.