1) Stir together yeast and water in a large mixing bowl. Let sit for 5 minutes and stir again to ensure yeast is well dissolved.
2) Add semolina flour to bowl and salt. Stir well to combine.
3) Add one cup of bread flour and mix to form a rough ball of dough. Turn this out onto a lightly floured surface.
4) Let the dough rest for 5 minutes, then knead for 10 minutes, sprinkling on more flour if the dough gets sticky. After ten minutes, the dough should be smooth and soft.
5) Move the dough to a bowl with a good drizzle of olive oil. Turn the dough to coat well with oil. Cover with a towel and let rise until it triples in size, probably 3 hours.
6) Punch the dough down, knead for another minute, and return to bowl to rise until it doubles, probably another 45 minutes.
7) Turn dough out onto a lightly floured surface, punch it down, and roll it into a rectangle about 18 inches high and 12 inches wide. Fold left 1/3 in and then right 1/3 over the top to form a cylinder. Form it into a smooth loaf.
8) Sprinkle a baking sheet with a good layer of corn meal. Add loaf to baking sheet seam side down. Let rise for 30 minutes.
9) Brush loaf with egg wash and sprinkle with sesame seeds.
10) Preheat at 425, put dough in the oven, then turn temp down to 380. Bake for 35-40 minutes or until dough is a very golden brown and is hollow when thumped.
11) Let cool for 30 minutes at least before slicing.