In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.
Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next.
Stir in the vanilla extract.
Gently fold in the self-raising flour until just combined.
Stir the date mixture into the batter until well mixed.
Bake the Pudding:
Pour the batter into the prepared baking dish and smooth the top with a spatula.
Bake in the preheated oven for 30-35 minutes, or until a skewer inserted into the center comes out clean.
Make the Toffee Sauce:
While the pudding is baking, combine the light brown sugar, double cream, butter, and black treacle (if using) in a saucepan over medium heat.
Stir constantly until the butter has melted and the sugar has dissolved.
Bring the mixture to a boil, then reduce the heat and simmer for about 5 minutes until the sauce has thickened slightly.
Serve:
Once the pudding is baked, remove it from the oven and let it cool slightly.
Cut the pudding into squares and pour a generous amount of toffee sauce over each piece.
Serve warm, preferably with a scoop of vanilla ice cream or a dollop of custard.
Enjoy your homemade Sticky Toffee Pudding!