Boil the pasta in salted water until al dente. Reserve 1/2 cup of pasta water before draining.
Heat the olive oil in a large skillet over medium-high heat and sauté the onions for 3 minutes.
Add the ground beef, Cajun seasoning, and smoked paprika. Cook and crumble until browned. Reduce heat to medium-low.
Stir in the minced garlic and cook for 1 minute, then add the cubed cream cheese, stirring until completely melted.
Pour in the heavy cream and Parmesan cheese, stirring until a smooth, thick sauce forms.
Toss the drained pasta into the skillet, adding splashes of reserved pasta water until the sauce reaches the desired consistency. Garnish with parsley and serve.