I learned how to make lángos from Eta in Tárnamera, Hungary. Köszönöm Eta!

Steps

1. Heat the milk and sugar over low heat until warm, but not hot then add the yeast. In a large workbowl add flour, salt, potatoes, eggs, and sour cream. Add wet ingredients to the dry ingredients and mix and fold for a good half hour. The dough should stretch well and be soft.
2. Warm a few inches of oil in your frying pan. Check the temperature by adding a small glob of dough to the oil. It there is no reaction the oil is too cold, but if the dough is thrown around the pan and there is a lot of sound the oil is too hot.
3. Working with oiled hands and using about a half a cup’s worth of dough at a time stretch it out until it looks something like a small pizza. Small holes are OK, and one in the middle is great to let steam through. Add the lángos disk to the pan by laying it down away from you to avoid hot splatter. Fry until brown, turn and repeat. Wick away the extra oil and serve by brushing on crushed garlic, then layering sour cream, and grated cheese.