Preheat oven to 180°c fanbake.
Peel and core the apples. Dice them and add to a pot with ¼ cup water, cinnamon and sweetener if you are using.
Cook over medium heat with the lid on for about 10 minutes, then when apples are softened, take the lid off and allow any liquid to evaporate, before setting the cooked apples aside.
If using seeds, grind them in your blender or food proccessor to form a flour. Place all the ingredients together in a large bowl and mix everything together. If it seems a bit dry and crumbly, add 1 Tbsp of water at a time, until it holds together nicely, when pressed.
Line a square slice tin with baking paper, and grease it.
Place half of the mixture on the tray and press down to spread out and form the base of the slice.
Spread the apples (now hopefully slightly cooled) on top of the base.
Take the remaining mixture and crumble it with your fingers on top of the stewed apples or fruit.
Cook in middle or lower rack in the oven for 25 minutes, or until the top is golden and the slice has risen.
Remove from the oven and let cool in the tin (you can put the whole tin in the fridge or freezer to help speed it up!) before removing and slicing. Store in the fridge or freezer.