Preheat the oven to 180C/370F/Gas 4.
Mix the dates, bicarbonate of soda and the water together in a bowl and leave to soak for ten minutes.
In a clean bowl, cream the butter and sugar together until light and fluffy.
Still stirring the butter mixture, gradually add the eggs, making sure they are well mixed in.
Still stirring, gradually add the flour, then add the date mixture.
Pour the mixture into a 20cm/8in square cake tin. Place into the oven and bake for 35-40 minutes, or until cooked through.
To make the sauce, melt the butter in a thick bottomed pan over a medium heat.
Add the brown sugar, vanilla pod and cream and stir well. Simmer for five minutes.
To serve, spoon out a portion of the pudding onto a plate and pour over the hot toffee sauce.