Sift the flour through a sieve. Heat the water until it is warm. Peel the onion.
Knead the dough. Pour warm water into a deep bowl. Add sugar, vegetable oil and salt. Add yeast. Stir. Gradually add flour, stirring constantly. Place the dough on a floured surface. Knead for 5-6 minutes until it becomes elastic and smooth. Cover with a clean towel and leave in a warm place for 1.5 hours.
While the dough is resting, prepare the filling. Cut the onion into small cubes. Pour vegetable oil into a frying pan and put on fire. Add onion. Add salt, ground black pepper and stir. Fry until golden, 4 minutes. Turn off the heat and transfer the filling to a clean bowl.
Prepare the roll. Place the dough on a floured surface. Using a rolling pin, roll out a layer 0.5 cm thick. Place the onion filling on the dough. Roll the dough tightly into a log. Bake the roll in the oven for 30 minutes at 180˚C.
The finished roll turns out neat and beautiful. Place it on a beautiful dish and serve.