Bring a large pot of heavily salted water to a boil. Add the rotini pasta and cook until al dente. Reserve at least 1/2 cup of starchy pasta water before draining.

Pat the bite-sized steak chunks completely dry with paper towels. Season generously with kosher salt and black pepper.

Heat neutral cooking oil in a large skillet over medium-high heat until shimmering. Add the steak bites in a single layer and sear undisturbed for 2-3 minutes until a dark crust forms. Flip and cook for 1-2 more minutes, then transfer to a plate.

Reduce heat to medium-low. Melt butter in the skillet with the beef drippings. Add minced garlic, tomato paste, smoked paprika, and red chili flakes. Sauté for 1 minute until fragrant.

Pour in the heavy cream, scraping up the browned fond from the bottom of the pan. Simmer for 2 minutes until slightly thickened. Stir in the parmesan cheese until melted and smooth.

Add the cooked rotini and rested steak bites back into the skillet. Toss vigorously for 1 minute, adding a splash of reserved pasta water if needed to loosen the sauce. Serve in a rustic bowl, garnished with freshly chopped green parsley and a sprinkle of red chili flakes.