Working with 1 piece of dough at a time, use your hands to roll the dough into an even 8-inch rope about 1/2 inch-thick, adding just enough flour to keep the dough from sticking if needed. Tie into a knot. Arrange the knots on the baking sheets, spacing them evenly apart. Cover loosely with plastic wrap and let rest until dough puffs slightly, about 15 minutes. When you press a finger into the dough, it should bounce back slowly.