Preheat oven to 180 C / Gas mark 4. Grease a two pint oven-proof bowl or pudding basin.
In large bowl, cream together butter and sugar. Add, a little at a time, beaten eggs, vanilla and flour, until well mixed. Fold in milk to achieve a smooth consistency.
Pour syrup in bottom of prepared basin and layer batter over the top. Cover basin with firmly tied baking parchment covered with foil. Line a roasting tin with a damp kitchen towel. Place basin on towel, inside roasting tin, and place roasting tin on oven rack. Fill roasting tin with boiling water to reach halfway up the sides of the basin.
Steam in the oven for 1 to 1 1/2 hours, or until pudding springs back when touched. Invert onto serving plate and serve warm.
Really easy and quick to make. I put treacle in the bottom of the basin, but not enough. I will be making this again, but next time experimenting with chocolate sauce or golden syrup. YUM!! - 18 Jun 2012