The apple pie gave me an idea. If what I like is baked apples, why not make just the filling and no pie. So this time around I simply cored and chopped an apple into thin slices, and tossed it in lemon juice.
I just spread the slices in a single layer on a baking sheet, then sprinkled some demarara sugar. Poured in two large slugs of balsamic vinegar to coat everything, and covered the baking sheet with a foil to stop the fruit burning. I baked it in a 200C oven for 10 minutes, then removed the foil and sprinkled some walnuts. Baked the apples for another five minutes or so, this time without the foil, until the juice has reduced to a thick syrup. They were delicious warm and straight out of the oven.