Chop the dates into small pieces and place them in a saucepan with boiling water and baking soda. Simmer over gentle heat for 5 minutes until the dates soften and the mixture darkens. Remove from heat and let cool slightly.
In a large bowl, cream together the softened butter and dark brown sugar with a whisk until the mixture is light and fluffy, about 2-3 minutes. Add the eggs one at a time, beating well after each addition, until the mixture is smooth and pale.
Stir in the vanilla extract. Gently fold in the self-rising flour until just combined, then add the slightly cooled date mixture, folding gently to incorporate evenly.
Pour the batter into a greased baking dish and smooth the surface with a spatula. Bake in a preheated oven at 180°C (350°F) for 30-35 minutes, until the top is golden and a toothpick inserted in the center comes out clean.
While the pudding bakes, prepare the toffee sauce by melting butter, dark brown sugar, and heavy cream in a saucepan over medium heat. Bring to a gentle boil and simmer for 3-4 minutes until the sauce is thick and glossy.
Remove the baked pudding from the oven and poke holes all over its surface with a skewer or fork. Pour the hot toffee sauce generously over the pudding, allowing it to soak in and coat the sponge evenly.
Let the pudding rest for about 10 minutes to let the flavors meld and the sauce to settle. Then slice into portions and serve warm, spooning extra sauce over each piece. Enjoy with cream, custard, or ice cream for an extra indulgent treat.
