Grease each of the ramekins with butter on the sides and base. Pour 2 tablespoons of golden syrup into the bottom of each dish.
Lightly beat the eggs and add in the butter, sugar and syrup (approx 3 tbsp). Combine well.
Sift the flour into the mixture and fold in. Add in the lemon juice, vanilla essence and milk.
Spoon the sponge mixture into each of the ramekins, filling to 1 cm below the rim. This allows room for the pudding to rise.
Place cling film over each of the puddings and twist to secure on one side. Place the dish in the slow cooker and fill with hot water to ¾ of the way up the dishes. Replace the lid and set to high for 1 hr 30 minutes.
Once the sponges are cooked (they should bounce back if you press gently), run a knife around the edge of each ramekin and turn out on a plate. If the pudding sticks, tap the underside of the ramekin.