Step 1: Cook the pasta according to package directions until al dente. Reserve about 1 cup of pasta water before draining.
Step 2: While pasta cooks, pat steak bites thoroughly dry with paper towels. Season with salt, pepper, and paprika.
Step 3: Heat olive oil in a large skillet (cast iron recommended) over medium-high heat until shimmering. Add 1 tbsp butter.
Step 4: Sear steak bites in batches, if necessary, to avoid overcrowding. Cook for 1-2 minutes per side for medium-rare, until a nice crust forms.
Step 5: Add remaining 1 tbsp butter and minced garlic (4 cloves) to the skillet with the last batch of steak. Cook for 30 seconds until fragrant. Remove steak bites from skillet and set aside on a plate, tented with foil.
Step 6: In the same skillet, melt 2 tbsp butter over medium heat. Add diced onion and cook until softened, about 3-4 minutes.
Step 7: Add 3 cloves minced garlic and cook for another minute until fragrant.
Step 8: Pour in heavy cream and chicken broth. Bring to a gentle simmer, stirring frequently.
Step 9: Stir in Cajun seasoning and cayenne pepper (if using). Let simmer for 2-3 minutes to allow flavors to meld and sauce to thicken slightly.
Step 10: Remove skillet from heat. Gradually stir in grated Parmesan cheese until smooth and fully incorporated. If the sauce is too thick, add a splash of reserved pasta water or chicken broth until desired consistency is reached. Taste and adjust salt and pepper if needed.
Step 11: Add the cooked and drained pasta to the Alfredo sauce. Toss to coat evenly.
Step 12: Gently fold the cooked garlic butter steak bites into the pasta.
Step 13: Serve immediately, garnished with fresh parsley and extra Parmesan cheese.