Grease a 1 Litre Pudding Dish with butter and set aside. Cream the softened butter together with the sugar. Add the lemon zest, eggs, milk and whisk again. Finally adding the dry ingredients.
Add the syrup, lemon juice and flaked salt into the bottom of the pudding dish, stir to combine and pour in the batter.
Cover the top of the basin with a centrally pleated circle of baking parchment and repeat with some foil. Tie securely with string, then make a loop in the string to create a carrying handle.
Put the pudding dish in a pot large enough to fit it with a lid – place it on a small trivet or upturned plate and fill with enough water to come at least halfway up the sides of the bowl. Cover with the lid and bring to the boil. Reduce the heat slightly and simmer gently for 1½ hours, topping up with just-boiled water when needed.
Remove from the pot when cooked and turn out onto a plate. Serve with cream or custard and enjoy.
