Mix flour, sugar, yeast, and salt to make the dough.
Let the dough ferment for about 1 hour.
Prepare the filling ingredients (sugar, nuts, cinnamon powder, etc.).
Take an appropriate amount of the fermented dough, flatten it into a circle, and wrap the filling inside.
Heat oil in a pan, place the hotteok dough in, and press it flat.
Cook both sides over medium-low heat until golden brown.