Combine flour, yeast, and salt in a large bowl. Add water, yogurt, egg, and oil, and knead with your hand mixer until dough is smooth. Cover bowl and transfer to refrigerator to proof overnight.
Pre-heat oven to 200°C/390°F. Cover baking sheet with parchment paper. Knead dough thoroughly, then form 15 buns and place on baking sheet. Cover with kitchen towel and proof again for approx. 5 – 10 min.
Bake on middle rack at 200°C/390°F for approx. 25 – 30 min. until bread buns are golden.