Place flour, sugar, butter, egg, yeast, salt, milk, and 45ml of water into a large bowl.
Stir the mixture by hand to form a dough.
Add another 15ml of water and massage the dough in the bowl for four minutes.
Knead dough on a floured surface for 10 minutes until smooth and elastic.
Let dough rise in a bowl for 40 minutes covered with a damp cloth.
Tip the risen dough onto a lightly floured surface.
Divide the dough into two equal halves.
Roll dough to 1cm thickness and cut using 8cm and 2cm cutters to form rings.
Spin each ring on your finger to slightly expand the center hole.
Place rings on an oiled tray and prove covered for 30 minutes.
Heat sunflower oil in a deep fat fryer to 180°C.
Fry each doughnut for one minute per side until golden brown.
Drain on kitchen paper and allow to cool.
Mix icing sugar with 25ml of water and lemon zest to create a thick paste.
Brush the tops of cooled doughnuts with icing and sprinkle with extra zest.
Set on a cooling rack to harden completely.