(Makes about 1 lb.)
In a saucepan, add salt to water and heat to a rapid boil. Meanwhile, crumble half of the mozzarella curd into a medium mixing bowl. Fill another medium mixing bowl halfway with ice and water.
Ladle the boiling salted water over the crumbled curd until cheese is completely submerged. Take a wooden spoon and slowly agitate the curd. The mozzarella will begin to look like it is melting.
Dip your hands into the ice bath to cool them down before touching the hot mozzarella. Very carefully gather the mozzarella in your hands and remove it from the bowl. While holding the cheese over the hot water, stretch it out between your hands. Tuck each end underneath, using your fingers to seal it to the string of curd, then stretch again. When the cheese begins to cool, return it to the hot water, dip your hands back into the ice bath, and pick the cheese up again. You’ll need to do this a few times until the cheese achieves a firm, shiny consistency. Then place it in the ice bath to cool for a couple of minutes.
Repeat process with the remaining mozzarella curd.
Serve immediately or refrigerate for up to three days.