And the answer is...

.

(click to enlarge)

..butternut squash!

Thanks for all of your guesses; most were on the right track! And thank you for your patience—it's been a busy week, and I didn't get this done as soon as I'd planned.

I'm happy with how the outside turned out, but I'm not wild about the inside (which you'd think would be more interesting). Sometimes I just lose interest in a piece that drags out too long; maybe that's the case here. But I do love to eat the inside—it's one of my favorite foods!