Generously butter a 1 litre pudding basin
In a bowl mix the flour, suet, sugar and salt
Gradually add cold milk until a soft but workable dough forms
Roll out about two thirds of the pastry and use it to line the pudding basin, leaving a little overhang at the rim
Prick the whole lemon a few times with a skewer
Pop half the butter and sugar in the bottom of the basin, add the lemon on top, and scatter the remaining brown sugar around the lemon and dot the remaining cubed butter over the top
Roll out the remaining pastry to form a lid
Place it over the filling and seal the edges well
Cover the basin with a sheet of baking paper and foil, pleated in the middle to allow expansion, then tie securely with string
Place the basin in a large pot with simmering water coming halfway up the sides and steam gently for 3½ hours, topping up the water when needed
