In a large bowl, combine ground beef, breadcrumbs, Parmesan cheese, egg, minced garlic, chopped parsley, salt, and black pepper. Mix until well combined. Form the mixture into meatballs, about 1 inch in diameter.

Cook the Meatballs

Heat olive oil in a large skillet over medium heat. Add the meatballs and cook until browned on all sides, about 8-10 minutes. Remove the meatballs from the skillet and set aside.

Make the Marinara Sauce

In the same skillet, add marinara sauce and bring to a simmer. Return the meatballs to the skillet, cover, and let simmer for about 15 minutes until cooked through.

Sauté the Vegetables

In a separate pot, sauté sliced mushrooms in a bit of olive oil until softened. Add fresh spinach and cook until wilted, about 2-3 minutes.

Cook the Cavatappi

Meanwhile, cook cavatappi pasta according to package instructions. Drain and set aside.

Combine and Serve

Toss the cooked cavatappi with the sautéed mushrooms and spinach. Serve the meatballs and marinara sauce over the pasta, garnished with extra Parmesan cheese if desired.