Preheat your oven to 350°F (175°C) and grease a 9x13 inch baking dish generously with butter, optionally lining the bottom with parchment paper.

In a bowl, toss the chopped dates with baking soda, then pour boiling water over them and let sit for about 10 minutes until softened.

Beat the softened butter with brown sugar in a large mixing bowl until pale and fluffy, about 3 to 5 minutes. Then add eggs one at a time, mixing well after each addition.

In a separate bowl, whisk together flour, baking powder, and salt.

Alternate adding the flour mixture and the date mixture (including soaking liquid) into the butter-sugar mixture, starting and ending with the flour. Stir in the vanilla extract at the end.

Pour the batter into the prepared dish and smooth the top. Bake for 30 to 35 minutes until a toothpick inserted comes out clean.

While the pudding bakes, melt butter in a saucepan over medium heat. Stir in brown sugar, heavy cream, and salt, bringing to a simmer. Cook for 5 to 7 minutes until thickened.

Once the pudding is out of the oven, poke holes in the top with a skewer and pour half the toffee sauce over it. Let it soak in and serve warm with additional sauce.