Add the mozzarella to a large microwave-safe bowl and microwave for about 1 minute.
Stir until cheese is completely melted. If needed, heat for an additional 30 seconds or until cheese is completely melted. Make sure to use pre-shredded mozzarella instead of shredding it yourself.
Allow to cool down for 30 seconds to avoid “cooking” the egg yolk when mixing. You
don't want to cool the cheese too long though because it needs to stay melted.
Add in egg yolk and gently fold the egg yolk into the melted mozzarella using a spatula, until you have a uniform yellow dough. You should obtain a smooth, slightly elastic texture. Form a ball with the mixture.
Place your dough on a parchment paper-lined baking sheet. Place another parchment
paper on top of the dough.
Use a rolling pin over the top piece of parchment paper, and roll dough or press down with your hand until it is 1/8 inch thick. Note that the dough is a bit elastic so take your time.
Remove the top piece of parchment and cut the dough into thin strips. Refrigerate the pasta for at least 6 hours or overnight, until completely dried up.
When ready to cook, bring a pot of water to boil. Have the water fully boiling before dipping the cheese pasta very quickly. Do not add salt to the water to cook the pasta as mozzarella is
already salty. Place the “pasta” in boiling water for just 30 seconds to maximum 1 minute – not more because it can start to fall apart.
Drain into a colander and run cold water over the pasta to prevent sticking.
Serve with your favorite sauce and toppings.