Prep the steak: Cut the steak into bite-sized pieces and season with salt and pepper.
Cook the steak: In a hot skillet, cook the steak bites in butter for 2-3 minutes until browned and cooked through.
Make the garlic butter sauce: Add garlic and cook for 1 minute, then stir in more butter and seasoning.
Prepare the pasta: Cook rotini according to package directions and drain.
Combine: Toss the cooked pasta with the garlic butter sauce and steak bites, then stir in Parmesan cheese.
Serve: Garnish with parsley and serve immediately.