In a small bowl, dissolve the yeast in warm water with a pinch of sugar. Let it sit for about 5 minutes until it becomes frothy.
In a large bowl, mix the flour, sugar, and salt.
Add the yeast mixture and vegetable oil to the flour mixture. Stir until a dough forms.
Knead the dough on a floured surface for about 5 minutes until smooth and elastic.
Place the dough in a lightly oiled bowl, cover it with a damp cloth, and let it rise in a warm place for about 1 hour, or until it doubles in size.
In a small bowl, combine the brown sugar, chopped nuts, sesame seeds, and ground cinnamon. Mix well.
Punch down the risen dough and divide it into 8 equal pieces.
Flatten each piece into a small disc about 1/4-inch thick.
Place a spoonful of the filling in the center of each disc.
Gather the edges of the dough around the filling and pinch to seal it, forming a ball.
Flatten each filled dough ball gently with your palm to form a thick pancake.
Heat 2 tablespoons of vegetable oil in a non-stick pan over medium heat.
Place the hotteok in the pan and cook for about 2-3 minutes on each side, or until golden brown and crisp.
Press down gently with a spatula to help the hotteok cook evenly and to flatten them slightly.
Enjoy your meal!