In a mixing bowl, combine the sourdough starter, warm water, olive oil, sugar, salt, parmesan, and sifted flour. Mix with a spoon until a shaggy dough forms, and leave it for about 5 mins. Then switch to hand mixing and do that for about 3 minutes, until the dough gets a bit smoother. The dough should almost resemble a stiff bread dough in consistency. Cover and let rest for about 30 minutes.

Place the dough into a lightly greased bowl, cover, and let rise until puffy and nearly doubled. In a warm kitchen, this usually takes around 4–6 hours.

After the bulk fermentation, prepare two pieces of parchment paper and flour one generously (use cornmeal if you have it, and flour if you don’t). Put the dough onto the floured piece of parchment paper, flour the dough as well, and start patting it and spreading it onto the parchment paper. Flour the dough again, and put the other piece of parchment paper over it. Then roll it as thin as possible, using a rolling pin. The shape doesn’t matter that much, but aim to spread it evenly between the pieces of parchment paper. When you’re done, take the upper parchment paper off.

Cut the dough into thin strips using a pizza cutter or sharp knife, cutting from one long edge of the dough to the other. Lightly brush the surface with olive oil, or use an olive oil spray for an even coating. Generously sprinkle your chosen topping over the strips.

To shape the grissini, pick up one strip and hold an end in each hand. Gently lift it off the work surface, fold it in half by bringing the ends together, and twist the two strands around each other. As you continue twisting, the dough will naturally stretch into a long breadstick.