• Peel the potato and cut it into large chunks. Place in a pot/pan and cover with cold water. Place on a medium heat and bring to a boil.
• Once boiling, reduce heat so the water simmers and cook until the potato is tender to a knifepoint. The timing will depend on the size of the pieces but it will take roughly 10 minutes after boiling, so check regularly a little before then. One tender, remove from the heat and drain - you don't want to overcook.
• Return the potatoes to the warm pot, uncovered and let the warmth help them steam and dry a little. Either place through a ricer or mash in a wide bowl/dish while they are still warm to help them lose a bit more steam. Allow to cool (some prefer to cook a day ahead, but at least not hot is best).
• Add the egg yolk, flour, butter and salt to the mashed potatoes, bring everything together and mix, but take care not to overmix. If the mixture is too sticky, add a little extra flour, but you don't want overly firm, and remember you will be rolling in flour.
• Lightly flour a clean work surface and take a small handful of the dough. Roll it out into a log, roughly 1 inch (2.5cm) diameter or slightly thinner. Cut the log into 1 inch (2.5cm) slices. Roll each piece with floured hands into finger shapes with pointed/tapered ends so they are slightly pointed on either side. Alternatively, you can just take a spoonful of the mixture, roll it then flatten to give the same finger with tapered end shape.
• Repeat with the rest of the dough and set the formed noodles aside on a floured board/baking sheet. I recommend forming all of the noodles before cooking.
• Bring a wide pot of water to a roaring boil (you want a good 2inches/5cm or more depth). Carefully add some of the noodles to the water, taking care not to overcrowd the pot. Once they rise to the surface, remove them with a slotted spoon and transfer to a plate/baking dish. Try to make sure they don't overlap or get too crowded. Repeat with additional batches.

For poppy seed sauce/serving

• Crush the poppy seeds into a powder, if not already crushed - you can use a spice grinder or pestle and mortar. Sift in the confectioner's/icing sugar then mix so evenly combined.
• When you are ready to finish the dish, warm a skillet/frying pan over a medium heat. I prefer to do one or two servings at a time as I find it easier to manage in a smaller skillet/frying pan, but do as you prefer. Melt the portion of butter for the amount you are cooking in the skillet until it is gently browned.
• Add the portion of potato noodles to the butter, turning now and then, so they are well coated. I like to gently brown and crisp them, cooking a few minutes, but more traditionally you don't, so do as you prefer. Add the portion of poppy seed-sugar mixture for the amount of noodles and toss so they are well mixed through. Serve warm, topped with a sprinkling more powdered sugar.