Pre-heat your oven to 180c/350f. Also grease and line an 8 inch square cake tin.

Add your butter and chocolate into a bowl and place this into your microwave. Heat until melted and smooth. Leave aside to cool down.

In a large bowl, add the eggs and both sugars. Whip these together until they lighten in colour and almost double in volume.

Whisk the melted butter and chocolate into this. Then add the flour, cocoa powder and salt. Whisk just until you get a smooth batter.

Pour this into your prepared tin, smooth the batter out, then leave this aside.

Add your peeled and chopped apples into a bowl, along with the rest of the ingredients for the apple filling.

Mix until the apples are fully coated with the other ingredients. Leave this aside too.

In a bowl, add the flour, oats, sugar and cinnamon. Mix these together.

Melt your butter, then add this into the bowl too. Mix until you get a crumbly mixture.

Add the apple filling into the tin, on top of the brownie batter. There will be a lot of juice from the apples in the bowl, try not to add this into the tin. You only want to add the apple pieces.

Now on top of the apples, add the crumble. Whiles sprinkling the crumble over the apples, I like to kind of squeeze it in my hands, just to get bigger clumps of crumble.

Once everything is in the tin, you can now bake it.

Bake for around 1 hour 20 minutes. It's done when a toothpick inserted into the centre comes out mostly clean. The toothpick will have the juices form the apples on it, and crumbs of brownie on it, that is fine. But if you see wet brownie batter, it needs to be baked for longer.

After 1 hour, I like to cover the top of the tin with some tin foil just so that the crumble doesn't brown too much

Once baked, leave to cool completely. Then chill it in your fridge for at least an hour, the longer the better.

Cut into it and then enjoy, they taste best warmed up a little!!