Combine the bread flour and fine semolina flour in a large bowl, then add the yeast mixture. Stir with a spoon or your hands until there is no dry flour left in the bowl.

Cover the bowl with plastic wrap and set aside at room temperature to allow the flour to hydrate.

Uncover the bowl. Add the salt, sugar, and olive oil and mix until incorporated.

Knead until smooth and elastic.

Transfer the dough to a lightly oiled bowl. Cover with plastic wrap and set aside at room temperature to rise.

Line a baking sheet with parchment paper. Uncover the bowl and invert it over a lightly floured surface, allowing the dough to gently detach.

Using a dough scraper or sharp knife, cut the dough into four pieces, each weighing about 100 grams. Working with one piece at a time, shape the dough into round buns, using a cupped hand to tighten the ball by rolling and dragging it over your work surface until it is a tight, compact mass.

Transfer the dough to the prepared baking sheet. Using a dampened hand, press each dough ball gently to flatten into a hamburger shape. Cover with plastic wrap and set aside to let the dough rise.

Preheat the oven to 400°F and place an empty ovenproof pot or pan at the bottom of the oven.

Uncover the dough and brush each ball with water, then sprinkle over the sesame seeds, dividing equally.

Transfer the baking sheet to the center rack of the oven and pour hot water into the pot or pan below, closing the oven quickly to trap the steam.

Bake until the rolls are golden and feel light when lifted.

Transfer the rolls to a wire rack to cool before using. The cooled rolls will keep in a sealed container at room temperature for up to 4 days. Toast before serving.