Looks kinda like a white patty pan or scallop squash. Simmered in butter, raw, stir-fried, stuffed, baked---it's all good. Welcome to the Forum!
at first glance i thought it was peeled pomelo Citrus maxima or Citrus grandis lol http://picasaweb.google.com/lh/photo/8TiW9Y86mEVthDJh4dOUtA