Mix all the ingredients for the dough and then leave it covered for an hour.
Divide the risen dough into six equal-sized balls. Then roll them out on a flour-covered work surface until they each form a long strand.
Divide the tomato sauce equally between the strands, spreading it out, but leaving a gap of about half an inch all the way round. Then sprinkle the mozzarella and salami on top. Next, turn the six strands of dough into rolls, by taking one of the free edges, folding it under the other and pressing them together.
Pinch the ends of three of the dough rolls together then weave them into a braid. To fix them in place, pinch the other three ends together to give the braid an even shape. Do the same with the other three rolls of dough.
To finish, spread egg yolk on the braids and sprinkle them with the sesame seeds. Then bake for 30 minutes at 340°F.
