Preheat your oven to 180ºc/160ºc fan and line two 8"/20cm round cake tins with parchment paper!
De-stone the dates, and chop up into quarters.
Add them to a bowl, along with the bicarbonate of soda and the boiling water and leave to sit for 10 minutes. Once sat, blitz the mixture into a puree with a food processor, or blender until smooth
Add your unsalted butter to a bowl, along with the dark brown sugar and beat until combined and smooth
Add the eggs into the mixture one at a time, and beat in each time.
Add in the flour, treacle, vanilla and pureed date mixture and beat again until smooth
Pour the mixture into the tin, and bake the cake in the oven for 35-40 minutes, or until baked through! I test with a skewer, and listen for the cake to make no sounds
Once baked, leave the cake to cool for 10 minutes in the tin, and then leave to cool fully on a wire rack.
For the Sauce
Whilst the cake is baking... make the sauce!
Add all the ingredients into a pan, and heat on a low heat till the butter has melted, and everything is mixed in.
Bring the mixture to the boil and boil for 1 minute.
Once the mixture has boiled, remove from the heat and leave the sauce to cool fully. Stir occasionally so a skin isn't formed
For the Buttercream
Add your butter to a bowl or stand mixer and beat on it's own for about 3-5 minutes until smooth and supple.
Add in the Icing Sugar and beat in until fully mixed in
Add in the cooled sticky toffee sauce and mix again, until delicious and perfect.
For the Decoration
Using your favourite piping tip, pipe your sticky toffee buttercream onto the cake!
Drizzle the cake with some more sticky toffee sauce, and then sprinkle with your favourite sprinkles!
Notes
This cake will last for 3-4+ days at room temperature
You can freeze the cake for 3+ months
The sauce will last for 3 days in the fridge if made separately
You can use shop bought toffee sauce if you want
The black treacle can swap to golden syrup
The dark brown sugar can swap to light brown soft sugar