Pour the water in a large bowl and sprinkle yeast all over it.
Wait for 5 minutes, then stir the yeast in.
Dissolve the sugar and salt in the yeasty water.
Stir in 3 cups of the bread flour and using a hand mixer, beat the mixture on medium speed for 2 minutes.
Add the remaining 4 cups of bread flour into the bowl and mix it in to form a loose and rough dough.
Turn the dough on to a clean, floured surface and knead with your hands until it is soft and smooth (4-5 minutes).
Place the dough in a large, greased bowl and cover with a damp kitchen towel. Keep the bowl in an oven or any dark place to rise undisturbed for 60-90 minutes. The dough will rise and double in size.
Punch the dough down and shape into a log. Break off 6 pieces and shape into balls.
Place the balls on two baking trays (3 balls on each) and cover with a damp kitchen towel. Keep the trays in the oven or any dark place for 20 minutes to rise again. Once risen, remove from the oven.
Preheat the oven to 500 degrees Fahrenheit. Spray the dough balls lightly with water and sprinkle the sesame seeds generously on them. Place the baking trays in the oven and bake for 2 minutes.
Decrease the temperature of the oven to 425 degrees Fahrenheit and continue baking the buns for 15 minutes more or until the tops have browned.
Take out the trays from the oven and transfer the bread to a wire rack to cool down.
Once cool, cut off the tops of the buns with a sharp bread knife and scoop out the bread inside to form a hollow inside each bun. The bread bowls are ready to use.