Answer:
I'm a small sweet cake, typically round, flat, and crisp. I come in a variety of flavors from chocolate chip to oatmeal raisin.
What can be opened but cannot be closed?
What food goes on and on without a beginning, middle, or an end?
The sun bakes them, The hand breaks them, The foot treads them, The mouth tastes them.
Squeeze it and it cries tears. As red as its flesh, but its heart is made of stone.
By Moon or by Sun, I shall be found. Yet I am undone, if there's no light around