Citrus. A real bang for your buck.
What you can do with an orange is a lot.
Aside from all the obvious uses (eating it fresh, drinking orange juice....mimosas, etc), in cooking and baking, there's so much you can do with just an orange and some sugar. For example when I make orange marmalade I use the whole fruit in the process. After removing the zest and orange segments I'm left with the seeds and membranes. So what do I do with all this crap? Well, what's neat about all this crap is it becomes a key ingredient and one you absolutely need if you're going to make cooked marmalade, jam or jelly - pectin. What is pectin? It's basically the "glue" that holds the marmalade together. It's found mostly in the white pith (albedo) of citrus fruits and in apples. If you're a keener check the Wikipedia definition as it goes way deeper than my tiny brain can handle. But if you want to know about marmalade I go in to detail on another post about how I make my marmalade. Moving right along....
The next thing you can make is candied peel. I always peel citrus since I don't like to waste anything. I store the peels in the freezer and when I need zest I just take out a couple strips. With an abundance of peels in the freezer (and ZERO room) I make candied peel often. The peels are brought to a boil in pot of water then strained. After about five water changes and a final cooking in sugar and water you get gorgeous strips of sweet citrus peel to use in your baking. I'll store them as-is in a plastic air-tight container and when I'm ready to use them I just take out what I need and finely chop or whiz 'em in the processor. These puppies go in my Sourdough Stollen Rolls!
So, utilizing the whole fruit (well minus the pith in the marmalade) we have pectin from the membranes and seeds, candied zest from the peels, orange syrup from cooking the peels and of course we have the marmalade from the rind and segments. Funny how I used to disdain the stuff for so long and now I'm sort of addicted to making it (and eating it). I guess I want other haters to realize how delicious it can be if done right. Well, done the way I like it - not bitter (and mine's not bitter!)