Apple and Bramble crumble cake

I was visiting my mother in law's allotment a month or so ago and was amazed at just how many blackberries she had growing there. I borrowed a tub from her and filled it with the intention of making some lovely seasonal bakes.

Something that I've always loved is crumble, served with custard though, not ice cream!
Though, it wouldn't have been very exciting just making a crumble and telling you all about it so I had a go at something a bit different that I found after a quick search around the Internet.

This crumble has a cinnamon sponge base, apple and blackberry filling and crumble topping. It looks impressive and smells amazing while it's in the oven.

For the sponge base:

150g caster sugar

3 large eggs
75g S/R flour

1/2 teaspoon of cinnamon 

Fruit filling:

2 cooking apples, peeled and chopped.

150g blackberries

For the crumble topping:

100g unsalted butter
100g Demerara sugar
1/2 teaspoon cinnamon 

Begin by creaming together the butter and sugar for the sponge base. When the butter and sugar are light and fluffy looking slowly add the egg. Then fold in the sieved flour/cinnamon and spoon the mix into a greased and lined 8" cake tin (preferably spring form).

Level out the cake mix and place the apples and blackberries on top.

Make the crumble mix by rubbing together the 

Bake in the oven (180c) for around an hour, though mine did take closer to an hour and a half. A skewer inserted into the middle (of the sponge) should come out clean.

Leave to cool in the tin and remove carefully. 

The simply pour over some delicious warm custard and enjoy!