Preheat oven to 350˚F. Butter and flour two 9inch cake pans.
Bring a medium pot of water to a boil, add dates and cook about 5 minutes or until you see the skins start to peel. Drain and let the dates cool enough to handle.
Meanwhile beat the butter and sugar in an electric mixer until light and fluffy. Then add the eggs one at a time, beating well after each addition and scraping sides.
Combine the flour and salt, and add into the batter mixing just until you have a lumpy dough.
Once the dates are cool, remove the skin and seeds, and roughly chop. In that same pot, combine dates with 3 ½ cups of cold water. Bring to a boil, stirring some to break up any sticky clumps, then let simmer for 1 minute. Remove from heat and stir in the baking soda (it will bubble up a bit).
With the mixer on low, pour in the warm date mixture, scrape down the sides halfway through and after (make sure to scrape all the way to the bottom). The batter will be very liquid at this point.
Finally, add the baking powder with the mixer on low. It will foam up a bit. Give the batter a quick turn with a spatula before dividing between the two cake pans.
Bake for 30-40 minutes, to test insert a toothpick or small knife into the center and it should come out clean.
For the Toffee Sauce: Combine butter, brown sugar, heavy cream, and vanilla in a pot. Bring to a boil and immediately turn heat to low and cook for a minute or two until slightly thickened and completely blended.
When the cakes are cool enough to handle, turn them out onto a cake stand or serving platter so that they are upside down. Poke cakes all over with a fork or knife and slowly pour toffee sauce over them, using an offset spatula or knife to spread evenly and to the edge so some of the sauce drips down the sides.
Recipe by Eat Some Wear Some at https://eatsomewearsome.com/sticky-toffee-pudding/