This came out great! I recommend covering the pan while the potatoes are cooking in the beginning so that the steam helps them to soften. I would also suggest adding the apples in a few minutes before the spinach unless you prefer them very crispy. I used honeycrisp apples and was very happy with the flavor. What you see here is the recipe tripled - for all of this I just squeezed half a lemon's worth of juice in at the end and that was just right for me.
This definitely took me a lot longer than 25 minutes to prepare with all of the chopping involved, but it's easy to make extra for leftovers!