Mix sugar, warm milk, warm water, vegetable oil, and yeast in a large bowl and combine them.
Add the flour, mahleb (optional), and salt and combine to form a nice, soft dough. Adjust the amount of flour if needed.
Knead until it smooth until it doesn't stick to your hands anymore.
Divide the dough into egg-sized balls (you should have around 22 balls).
Flatten the ball on the lightly oiled work surface into a circle with your hands.
If you want to make round shape buns, put a spoonful of cheese mixture in the middle of the pastry and fold the dough over the mixture to meet in the center, and gently pinch the edges with your fingertips to seal and place the seam side down on a baking sheet lined tray.
Shape the rest of the dough balls and place them on a baking tray a few centimeters apart from each other to make sure there is enough space for proofing.
If you want to make half-moon-shaped buns, put a spoonful of cheese mixture on one side of the pastry and fold the other side on top and gently press the edges to make sure they stick to each other.
Shape the rest of the dough balls and place them on a baking tray a few centimeters apart from each other to make sure there is enough space for proofing.
Brush with egg wash and sprinkle sesame seeds or nigella seeds on top.
Let them rise in a warm place until they double in size (it takes 45 minutes to an hour depending on the room temperature).
Preheat the oven to 360° F (180° C) fan oven.
Bake them until golden brown (usually takes around 25-30 mins depending on the performance of your oven).