1. 1. Generously grease a 1-quart pudding basin.

2. 2. Pour the golden syrup or treacle into the bottom of the basin.

3. 3. Cream together the softened butter and granulated sugar in a large bowl until light and fluffy.

4. 4. Beat in the eggs one at a time, ensuring each incorporates fully before adding the next.

5. 5. Gradually fold in the self-rising flour, alternating with the milk, starting and ending with flour.

6. 6. Stir in the vanilla extract.

7. 7. Carefully spoon the sponge mixture over the syrup in the basin.

8. 8. Cover the basin tightly with parchment paper, then foil, securing with kitchen twine.

9. 9. Place the basin into a large pot with boiling water, ensuring the water comes halfway up the sides of the basin.

10. 10. Steam your Treacle Sponge Pudding for 1.5 to 2 hours, checking the water level occasionally and topping up if needed. The Treacle Sponge Pudding will turn golden and feel firm.

11. 11. Carefully remove the Treacle Sponge Pudding from the pot, let it rest for 5 minutes, then invert it onto a serving plate.