Cook the pasta according to package directions in salted, boiling water. Reserve 1 cup of pasta water before draining.

While pasta cooks, season steak strips with salt, pepper, and 1 tsp of Cajun seasoning. Heat olive oil in a large skillet over medium-high heat. Sear the steak for 1-2 minutes per side until browned. Remove steak and set aside.

In the same skillet, add the sliced onions and bell peppers. Cook for 4-5 minutes until softened. Add minced garlic and cook for 1 minute more.

Reduce heat to medium-low and pour in the heavy cream and remaining Cajun seasoning. Bring to a gentle simmer. Stir in the grated Parmesan cheese until the sauce is smooth and melted.

Add the drained pasta and the seared steak (with juices) back to the skillet. Toss to combine. If needed, thin the sauce with a splash of reserved pasta water.

Serve immediately, garnished with fresh parsley and extra Parmesan.