Preheat your oven to 350°F (175°C). In a large mixing bowl, combine the egg, chopped parsley, dried oregano, minced garlic, salt, pepper, ground beef, ground pork, breadcrumbs, and grated Parmigiano-Reggiano. Mix gently until just combined, then shape the mixture into golf ball-sized meatballs. Place them on a baking sheet and bake for about 20 minutes, or until they are golden brown and cooked through.

While the meatballs are baking, melt 3 tablespoons of butter in a large skillet over medium heat. Add finely chopped yellow onion and minced garlic, sautéing for about 5 minutes, or until the onion becomes translucent and fragrant. Pour in 3 cups of high-quality marinara sauce and sprinkle in ½ teaspoon of sugar, letting the sauce simmer for another 5 minutes to enhance the flavors.

Once the sauce has simmered, reduce the heat to low and stir in 1½ cups of heavy cream. Continue stirring until the cream is fully incorporated, creating a luscious, creamy texture.

In a large pot, bring salted water to a boil over high heat, then cook 12 oz of spaghetti following package instructions until al dente, about 8 to 10 minutes. Once cooked, drain the pasta in a colander, but reserve about a cup of the starchy pasta cooking water.

Add the drained spaghetti directly into your creamy marinara sauce. Toss gently to coat the pasta evenly, and use the reserved cooking water as needed to achieve your desired sauce consistency.

Carefully add the baked meatballs into the pasta and sauce mixture. Gently toss everything together to combine. Allow this to heat through on low for about 2-3 minutes.

Once everything is heated, serve your Creamy Spaghetti and Meatballs in warm bowls. For an extra touch, garnish with additional grated Parmigiano-Reggiano and a sprinkle of fresh parsley.