Grease and line a 30.5x10x2.5cm tin
Filling: put the dates, flour, water, chocolate and a few drops of vanilla essence in a small saucepan and cook gently for 10 mins. Leave to cool while preparing crumble mix.
In a bowl mix together the flour, oats, and sugar and stir in the butter.
Spread half the crumble over the base of the tin, press down well.
Cover with the filling.
Cover this with the remainder of the crumble.
Press down with a round bladed knife.
Bake in centre of oven (190*C) for about 25 minutes (until golden brown)
Cool in tin for 15 minutes then turn onto board to cut into fingers.
Makes about 12