Pre-heat your oven to 180°C (Gas mark 4)
Grease and line a 23cm square tin and set to one side
In a bowl, put the flour, sugar butter almonds and oats for your crumble and rub between your fingers until its well combined and doesn't stick to your fingers. You can pulse blitz this in a food processor to get the same result. Just be careful of your fingers when working with any food processor. When ready, put to one side somewhere cool.
In a large bowl, cream together the butter and sugar until it is pale and has risen in volume. Add the vanilla bean paste, eggs and water and using a spatula to fold through the mix, add the self raising flour.
Fold through half the apples and the blackberries and carefully pour into the tin.
Scatter the remaining apples and blackberries on top and cover with the crumble mix.
Bake for 35-40 minutes or until cooked through. Use a clean knife to test by piercing the highest point. The knife will leave the cake clean if it's done.
Gently remove the cake from its tin and allow to cool before cutting into squares. 12 is a good number for this cake!