Start by bringing a large pot of salted water to a boil. Add the linguine and cook it according to package instructions until al dente. Drain and set aside, reserving ½ cup of pasta water for later use.
While the pasta is cooking, pat the sirloin steak dry with a paper towel to remove any excess moisture. Season both sides with salt and black pepper.
Heat a large skillet over medium-high heat. Add 1 tablespoon of butter and let it melt. Place the steak in the skillet and sear for 3-4 minutes per side, depending on your desired doneness.
In the same skillet, reduce the heat to medium and add the remaining 1 tablespoon of butter. Add the minced garlic and sauté for 1-2 minutes until fragrant. Pour in the heavy cream, stirring continuously. Sprinkle in the grated Parmesan and stir until smooth.
Add the cooked linguine to the skillet, tossing it in the garlic butter sauce. If the sauce is too thick, add a bit of the reserved pasta water until you reach your desired consistency.
Slice the rested steak into thin strips. Place the steak on top of the creamy pasta and give it a final toss to coat everything in the sauce.
Garnish with fresh parsley, extra Parmesan, and a sprinkle of red pepper flakes if you like a little heat. Serve immediately and enjoy.