Bring a large pot of salted water to a boil and cook rotini pasta according to package directions until al dente. Drain and set aside.
In a large skillet, heat olive oil over medium-high heat. Add ground beef, onion, and bell pepper.
Cook beef until fully browned, breaking it into small crumbles with a spatula. Drain excess fat from the pan.
Stir in minced garlic and Cajun seasoning. Cook for 1 minute until fragrant.
Pour in the beef broth to deglaze the pan, scraping up any browned bits from the bottom.
Reduce heat to medium-low and stir in the heavy cream. Simmer for 3 to 5 minutes until the sauce begins to thicken slightly.
Add the grated Parmesan cheese and stir until completely melted and the sauce is smooth.
Incorporate the cooked rotini into the skillet, tossing well to ensure even coating in the sauce.
Season with salt and pepper to taste. Garnish with chopped parsley and serve immediately.