In a large pot, melt 2 tablespoons of butter over medium heat. Add the diced onion and sauté until translucent, about 3-4 minutes.
Increase the heat to medium-high and add the ground beef. Cook until browned and crumbled, about 5-7 minutes. Drain excess fat if necessary.
Stir in the minced garlic and cook for another minute until fragrant.
Add the dry pasta to the pot along with beef broth, heavy cream, Italian seasoning, and a pinch of salt and pepper. Stir well to combine.
Bring the mixture to a boil, then reduce the heat to low, covering the pot. Let it simmer for about 15 minutes, stirring occasionally, until the pasta is cooked and the sauce is creamy.
Once cooked, remove the pot from heat and stir in the remaining 2 tablespoons of butter and the grated Parmesan cheese until melted and well incorporated.
Taste and adjust seasoning if necessary.
Serve warm, garnished with fresh parsley on top for a pop of color.
Notes
Adjust seasoning to taste and serve with fresh parsley for garnish.