Step-by-step preparation:
Preparing the yeast dough: In a large bowl, mix warm water, sugar and yeast. Leave for 5-10 minutes for the yeast to "activate" (foam should appear). Add salt and 1 tbsp. sunflower oil. Gradually add the sifted flour, kneading a soft, elastic dough. Knead for about 7-10 minutes, until the dough stops sticking to your hands. Grease a clean bowl with a small amount of oil, put the dough, cover with a towel or cling film and leave in a warm place for 1-1.5 hours to rise. The dough should increase in volume by 2 times.

Preparing the filling: Peel the onion and cut into small cubes. Heat 2 tbsp. sunflower oil in a frying pan. Add the onion and sauté over medium heat, stirring, until golden brown and soft (about 7-10 minutes). Cool. Cut the ham into small cubes. Grate the cheese on a large grater. In a deep bowl, combine the cooled onion, chopped ham and grated cheese. Mix well.

Forming the buns: Knead the risen dough well and divide it into 2 equal parts. Roll each part out on a floured surface into a thin oval (approximately 30x20 cm). Arrange the ovals vertically. Place half of the filling in the center of each oval, leaving the edges free (approximately 2-3 cm on each side). With a sharp knife, make cuts along the edges of the dough, forming strips 1.5-2 cm wide on both sides of the filling (without cutting to the central part with the filling). Starting from the top, alternately place the dough strips on the filling, "braiding" them crosswise to make a "pigtail". Secure the ends well.

Baking: Line a baking sheet with parchment paper. Carefully transfer the formed buns to the baking sheet. In a small bowl, lightly beat the egg yolk with 1-2 tsp. water. Brush the buns with the resulting mixture. Sprinkle each bun with dried basil and oregano. Bake in an oven preheated to 180°C for 30-40 minutes, or until golden brown and cooked through.

Enjoy!