Make the cake

1. Preheat the oven to 350. Butter a 8 X 8 inch baking pan.
2. In a medium bowl, combine the dates and baking soda. Pour the boiling water over the top and set it aside for 15-20 minutes to allow the dates to soften. Puree the mixture in a blender or food processor, or mash with a fork.
3. Melt the butter and set aside. 
4. Whisk together the flour, baking powder and salt. Set aside.
5. In a large bowl whisk together the eggs, sugar and vanilla until pale and frothy. Whisk in the sourdough discard. Whisk in the date paste and melted butted until well combined, then stir in your flour mixture.  
6. Pour the batter into the prepared pan and smooth out the top. Bake for 35–40 minutes, or until a toothpick inserted into the center comes out clean. Remove the cake from the oven and poke holes all over,  pour half of the toffee sauce. Allow to soak for 30 minutes.
7. Serve warm or at room temperature with vanilla ice cream and more sauce.

To make the toffee sauce 

1. While the cake is baking make the toffee sauce. Place butter in a small saucepan over medium heat and melt, add brown sugar and continually stir them both together until sugar has dissolved and it starts to bubble.
2. Gradually add cream ( it will bubble a little ) while whisking. Scrape in the seeds from the vanilla bean (if using) and the pod and simmer on low heat for 5-7 mins, whisking until smooth and slightly thickened.
3. Remove from heat and add a pinch of salt. If using vanilla extract or bean pasta, add it with the salt. Set aside to cool.