To cook Potato, I recommend to use steamer or microwave. If you boil in water, you would need more Flour.
Simply steam Potato until tender. If you use microwave, place Potato pieces in a large heat-proof bowl and cover with a plate, cook for 3 minutes, toss over and cook 2 more minutes. Then toss again carefully because it is very hot, cook 2 more minutes. Cook until tender.
Mash cooked Potato and season lightly with Salt and White Pepper.
Transfer to another cold bowl if you have one. Add Plain Flour and Parmesan, and combine until crumble texture. Add Egg and mix to form a firm dough.
Turn onto a lightly floured surface and divide the dough into 4 portions. Roll 1 portion into a log about 2cm in diameter, and cut into 2cm pieces. Roll each piece into a ball. Use a floured fork to roll over each ball. Repeat with the remaining dough.
Cook Gnocchi in a saucepan of boiling salted water, but DO NOT overcrowd as they can stick together. Cook until they rise to the surface. Enjoy with your favourite sauce.
