Mix 1 1/4 cup bread flour, 1/4 tsp yeast, and 1/3 cup + 2 tbsp water in a small bowl. Cover and proof for 2 hours. Punch down and form into a ball. Place the dough in an oiled bowl, cover, and refrigerate overnight or up to 3 days.
Pull the starter from the refrigerator an hour before making the bread. In a stand mixer with a dough hook attachment mix the bread flour, salt, sugar, yeast, and malt powder. Break the starter into pieces and add them to the mixer. Mix in the olive oil and milk. Mix for 5 minutes. Place the dough in an oiled bowl and cover for 1 1/2-2 hours.
Punch down the dough. Shape the dough into a large round. Dust a sheet pan with semolina or cornmeal. Place the dough on the pan and press into a round loaf. Cover and proof for 30-60 minutes. Preheat the oven to 350 degrees. Brush the dough with egg wash and sprinkle on sesame seeds. Bake the bread for 25 minutes. Remove from oven and cool to room temperature.