Preheat the oven to 350 degrees F. Line an 8X8 baking dish with parchment and set aside.
In a large mixing bowl, whisk together the dry ingredients. Mix in the syrup and coconut oil and crumble with your hands until it resembles a coarse, sandy texture. Remove 1/2 cup of the dough for the topping.
Add the flax egg to the bowl and stir to form a sticky dough. Transfer the dough to the baking pan and press it evenly with your fingers or a flat-bottomed glass.
Toss all the apple ingredients together until combined and pour on top of the base. Spread out evenly with a spatula. Crumble the reserved oat topping over the jam.
Bake in the center of the oven for 40 - 45 minutes until the oats are golden brown. Check after 30 and cover with foil if the topping is getting too brown. Remove and cool for 30 minutes, then transfer to the fridge and cool completely. Slice into squares and serve!