Name that vegetable!

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I've been searching for a very long time for a Chinese restaurant that makes the really, really wide chow fun noodles, not the fettuccine-sized ones.  Just when I'd given up hope, sidebernie discovered that the takeout place they sometimes ordered from on game night had these noodles, so he promised to buy me some the next time he ordered from them.  And last night he delivered on his promise, so I had yummy chow fun for lunch!

However, can anyone tell me what the yellow vegetable is in the following photo?  I've been unable to identify it, and identify it I must, lest I lose my reputation as a foodie:




Update:  The underside looks squash-like.