Whisk the semola, bread flour, yeast, and fine sea salt together in a 28 cm / 11-inch mixing bowl. Pour in the 300 ml lukewarm water and stir until no dry flour remains.

Knead on an unfloured counter for 8 to 10 minutes, or 6 minutes in a stand mixer with the dough hook on medium-low, until the dough is smooth and firm. It should feel slightly tacky but not stick to the counter. Cover the bowl and let it rise for 60 minutes, until puffed by about half.

Divide the dough into 8 pieces of about 100 g each. Roll each into a rope about 25 cm / 10 inches long, overlap the ends by 2 cm, and press hard to seal into a ring. Set 4 rings on each of two parchment-lined 33 x 46 cm / 13 x 18-inch sheet pans, cover loosely, and rest for 30 minutes while the oven heats to 200 C / 400 F.

Bake both pans for 20 minutes, swapping their positions halfway, until the rings are pale gold and sound hollow when tapped underneath. Cool on a wire rack for 15 minutes, then lower the oven to 150 C / 300 F.

Split each ring horizontally into two thinner rings with a serrated knife, using a gentle sawing motion and keeping your other hand flat on top. Set the halves cut side up on the two pans.

Bake for 40 minutes, swapping the pans halfway, until the cut sides are pale gold and each frisella is dry through. Cool one half for a few minutes and break it open. It should snap with no soft spot in the center, and if it bends, bake the batch 10 minutes more. Cool completely on the racks, about 20 minutes, before storing.

While the friselle cool, toss the chopped tomatoes with the flaky sea salt, oregano, and 3 tbsp of the olive oil. Let the mixture stand for about 10 minutes, until the juices pool in the bowl.

To serve, dip each frisella in the 500 ml cold water for about 10 seconds, turning once, and shake off the excess. The surface should give slightly while the center stays firm. Set 2 on each plate, spoon over the tomatoes and their juices, and drizzle with the remaining 3 tbsp olive oil. Serve within 15 minutes.