Place the flour and the salt in a large bowl and add the sesame seeds and sugar. Mix it all together and make a well in the middle.
In another small bowl add the yeast and a little bit of the lukewarm water and stir it through. It should get a bit frothy. Add the rest of the water and pour this into the well you made in the flour mixture. Stir it through so it forms a wet dough. Sprinkle with a bit of flour, cover with a clean tea towel and set in a warm spot until it starts to rise and bubble.
Now add the melted butter and mix everything together to a smooth dough. Knead the dough on a flour covered surface or use a machine with a dough hook. Knead for about 8-10 minutes until you have a smooth and elastic dough. Put it in a bowl that is rubbed with a little oil to prevent sticking, cover with greased plastic foil and leave to rise in a warm spot for 45-60 minutes until the volume has doubled.
Beat the dough back on a flour covered surface. Make an oval or round shape out of it and put it on a baking tray brushed with a little butter or oil. Cover the dough with greased plastic foil and leave it in a warm spot for another 30-40 minutes to rise until the volume has doubled.
Preheat the oven at 220 ° C (400.˚F) Mix the egg white and the salt and put some on top of the bread. Sprinkle with the sesame seed and cut with a sharp knife over the top of the bread. Bake the bread for 20 minutes and put the temperature down to 180 °C and bake for another 10 minutes until it sounds hollow when you tap the bottom of the bread. Leave to cool on a wire rack.