Pre-heat oven to 350 degrees.
Place chopped rhubarb and apple in a medium casserole dish or oven-safe pot.
Add remaining ingredients (retaining the zest of one orange and vanilla ice cream for later) and gently toss. I advise tasting one chunk of apple and one chunk of rhubarb at this stage. They will both be nicely sugar-coated and crisp.
Bake uncovered for 15 minutes. Stir (it will smell so good). Bake an additional 15 minutes. Fruit should be tender and kitchen should smell even better than it did the first time you opened the oven door.
And...that is it. You are done. Can you believe it's that easy?
I let this batch cool slightly (5-10 minutes), spooned some into a bowl, and topped it with a small scoop of vanilla ice cream. I ate the rhubarb as the ice cream melted on top. Superb! My husband had fallen asleep at this point (my experimenting went a little late), but I woke him and gave him a bite. He liked it too. He even held his eyes open for a couple additional tastes. I went to sleep satisfied.