Grease a 1.2-litre pudding basin.
Mix together the flour, suet, sugar and salt.
Whisk together the eggs, milk, vanilla and lemon zest.
Pour into the dry ingredients and stir until you have a dropping batter—it should slowly fall from the spoon rather than hold its shape.
Fold through the sweetened gooseberries.
Transfer to the basin, cover with a pleated sheet of baking paper and foil and tie securely.
Steam gently for 1 hour 45 minutes to 2 hours, topping up the water when needed.
Serve immediately with plenty of hot custard.
