1. Heat olive oil in a large skillet over medium-high heat. Season the beef strips with salt and pepper, then sear in batches until browned on both sides. Set aside.

2. Cook the spaghetti in salted boiling water until al dente. Reserve 1 cup of pasta water, then drain.

3. In the same skillet, reduce heat to medium-low and melt the butter. Add garlic and sauté for 1 minute until fragrant.

4. Stir in the heavy cream and Cajun seasoning. Let simmer for 2–3 minutes, then add the Parmesan and stir until melted. Adjust seasoning with salt or chili flakes if desired.

5. Add the cooked spaghetti to the skillet and toss to coat in the sauce. Add a splash of pasta water if the sauce needs thinning.

6. Return the seared beef to the skillet and stir to combine. Let everything heat through, about 1–2 minutes.

7. Garnish with chopped parsley and extra Parmesan before serving.