Preheat the oven to 180℃, butter a 9inch baking dish as set aside.
In a large bowl, add the dates (make sure no seeds are there) add the coffee, baking soda and pour over the hot water. Set aside for 10 mins. You can use the mixture as it is (which will be very chunky) or blend it into puree.
Beat the butter until pale and light. Add the sugar and treacle, beat again for a few minutes until dissolved and the mixture is fluffy.
Add the eggs and beat well until combined.
Add the flour, baking powder, salt and vanilla. Mix until just combined and there are still a few flour pockets.
Add the date mixture and fold everything together until its a smooth batter.
Pour into the prepared tin and bake for 30-35 mins until a knife inserted into the center comes out with moist crumbs.