S.B.
have no idea if this is your issue or not, but because you mention that you might have noticed a texture issue ... my son has a sensory issue. never heard of it before my son at 2yrs old decided to stop wearing clothes, but one aspect is eating.
For my son, he wouldn't touch anything mushy - still doesn't eat the standard macaroni and cheese or chicken nuggets, but is content to eat a dinner of green salad with italian dressing and pickles but will also eat almost anything sweet.
he is darn stubborn and i constantly debate whether he's just insisting on only eating what he wants, but i do have a diagnosis that states his sensory system didn't quite develop along with the rest of him and sweet and sour things may be the only things he really tastes.
however, if it's the same issue with your daughter, the key to getting them past it is to deluge them with sensory experiences that she's probably not just getting from pb&j.
check out the Out of Sync Child from the library and see what you think.