I can't eat apples they spike me, but I do make rhubarb and strawberry crumble, try this, just swap the rhubarb and strawberries for apple. This is the recipe I always use, so I know it works.
200g Almond flour
250g rhubarb
100g strawberry's
20g Splenda
60g softened butter
I stewed the rhubarb in the splenda until soft, then put it and the strawberry's into an ovenproof dish. I mixed the almond flour and butter until it resembled breadcrumbs, and covered the fruit mixture. It cooked at around 180 degrees for 30-40 minutes. I ended up serving it with lashings of single cream.