For the poppy seed noodles, boil the potatoes. Leave to stand for 3-4 minutes in the open saucepan, peel while hot and press through. While still hot, knead together with the remaining ingredients to form a dough.
Add the eggs last. Form elongated noodles, place in boiling water, reduce temperature and let stand for 5-10 minutes. Do a cooking test.
Drain the pasta and toss in melted butter. Sprinkle vanilla sugar, poppy seeds, sugar, possibly drizzle rum. Toss carefully. Serve sprinkled with powdered sugar.