Bring a large pot of salted water to a boil. Add the fettuccine pasta and cook according to package instructions until al dente. Reserve 1/2 cup of pasta water, then drain the pasta and set aside.
Pat the steak strips dry with paper towels. Season them generously with salt and half of the cracked black peppercorns. Heat olive oil over medium-high heat in a large skillet. Add steak strips in a single layer and sear for about 2-3 minutes per side until browned but still tender. Remove steak from the skillet and set aside.
In the same skillet, reduce heat to medium. Add minced garlic and sauté for 30 seconds until fragrant. Stir in the remaining cracked black peppercorns. Pour in the beef broth and scrape any browned bits off the bottom of the pan to enhance flavor. Let it simmer for 2 minutes.
Reduce heat to low and stir in the heavy cream and Dijon mustard. Allow the sauce to gently simmer and thicken for about 3-4 minutes, stirring frequently. Adjust seasoning with salt if needed.
Add grated Parmesan cheese to the sauce, stirring until melted and smooth. Return the steak strips to the skillet along with the cooked fettuccine. Toss everything together to coat the pasta evenly in the creamy sauce. If the sauce is too thick, add reserved pasta water a tablespoon at a time to reach your desired consistency.
Transfer the pasta to plates or a large serving bowl. Sprinkle freshly chopped parsley over the top for a burst of color and freshness. Serve immediately.