Grate cheese and set aside.

Chop parsley and set aside.

Whisk together cornstarch and cold water in a small prep bowl to make a slurry, then set aside.

Grate onion into another small prep bowl and set aside.

Combine beaten egg, grated onion, ½ tsp salt, ½ tbsp pepper, allspice, and nutmeg in large bowl. Whisk together, then add ground beef and breadcrumbs. Using clean hands, mix together beef, breadcrumbs, and other ingredients in the large bowl until combined.

Roll meat mixture into small, golf ball-sized meatballs and place on a dinner plate. (Should yield 20-25 meatballs.)

Heat olive oil in a large Dutch oven over medium-high heat. Place meatballs in a single layer in the bottom of the pot, leaving some space between each meatball. Brown meatballs on one side, about 3 minutes, then flip and brown on the other side.

Once meatballs are browned on both sides, lower the heat to medium. Add the chicken broth, stirring with a spatula to deglaze the bottom of the pot. Add mustard, Worcester sauce, ½ tsp salt, ½ tsp pepper, and milk, stirring continuously.

Bring liquid to a boil, stirring regularly to ensure that milk doesn’t curdle. Once boiling, add the egg noodles to the pot.

Stir constantly until the pasta is cooked to al dente and the liquid has reduced by half, around 8-9 minutes.

Remove pot from heat, then add 1.5 cups grated cheese and half the chopped parsley. Stir to combine.

Slowly whisk your cornstarch and water slurry into the pot. Stir with the spatula and cook 1-2 minutes, until sauce has slightly thickened.

Serve immediately, garnishing with additional grated cheese and remaining chopped parsley.