Dissolve the yeast in the warm water, in a small bowl and keep aside.
Put the flour and the salt in the food processor bowl (or a largish regular bowl if kneading by hand) and pulse a couple of times to mix. Add the butter pieces and pulse until the butter is well mixed and the flour-butter mixture looks powdery.
Add the yeast-water mixture and pulse till it all comes together as a ball. Do not over process or knead. Place the ball of dough in a oiled bowl, turning it so it is well coated with the oil. Cover the bowl, and let the dough rise quite a bit. This dough does not really double in volume, but it should look u201cpuffyu201d after about an hour or so. When you pinch off a bit from the top you can see the interior looking a bit like honeycomb. Press down the dough and deflate it, wrap it in cling warp and refrigerate it for at least one hour or up to 24 hours.
When ready to make the cookies, take the dough out and lightly roll it out into an approximately 6u201d square. If the dough feels sticky, scatter a little sugar on it. Using a pizza wheel cut the dough into four strips of equal width. Cut each strip into 6 equal pieces, by cutting across, making a total of 24 pieces. The measurements are not very critical in this part because this just makes it easier to have 24 equal sized bits of dough, as compared to pinching of bits of the dough.
Roll each piece into a pencil thick u201cropeu201d about 5u201d long. Sprinkle a little sugar on your work surface and roll the u201cropeu201d in it so the sugar crusts the dough uniformly. Form the u201cropeu201d into a loop crossing it over before the ends.
Place the Torcettini on parchment lined baking sheets, leaving 1 1/2" between them. Leave them for about 20 minutes or so till they rise/ puff up slightly. They will not u201cpuff upu201d much, like bread, but the u201cpuffu201d will be visible.
Bake them at 160C (325F) for about 25 minutes till theyu2019re a nice golden brown. Cool the cookies completely, on a rack. Store them in an air-tight container at room temperature. Although, I found them best the day they were baked.