Preheat the oven to 190°C.
Grease a 20cm square cake tin with butter and dust with flour.
Whisk the butter and sugar together until blended.
Boil the dates with 300ml of water in a saucepan.
Mix golden syrup, treacle, vanilla, and eggs into the butter mixture.
Fold in the flour at a slow speed and then turn off the mixer.
Purée the hot date mixture, stir in bicarbonate of soda, and combine with the batter.
Pour batter into the tin and bake for 40 to 45 minutes until firm.
Dissolve the sauce sugar, butter, treacle, and syrup in a pan over gentle heat.
Add cream, bring to a boil, and stir until the sauce thickens.
Cut the cooled pudding into squares and serve with the hot toffee sauce.