01 - Bring a large pot of salted water to a boil. Cook the cheese tortellini according to package directions until tender. Drain thoroughly and set aside.
02 - Pat the sirloin pieces dry with paper towels. Season generously with salt and freshly ground black pepper on all sides.
03 - Heat olive oil in a large skillet over medium-high heat until shimmering. Add the seasoned steak pieces in a single layer and sear for 2–3 minutes per side until a deep golden-brown crust forms and the meat reaches your preferred doneness. Transfer the steak to a plate and set aside.
04 - Reduce the heat to medium. Add the unsalted butter to the same skillet, allowing it to melt and foam. Sauté the chopped shallots and minced garlic, stirring frequently, until fragrant and softened, about 1 minute.
05 - Pour the heavy cream into the skillet, stirring to scrape up any browned bits from the bottom. Bring the mixture to a gentle simmer and cook for 2–3 minutes, allowing the sauce to reduce and thicken slightly.
06 - Gradually stir in the grated Parmesan cheese, continuing to stir until fully melted and the sauce is smooth and velvety.
07 - Return the cooked tortellini and seared steak pieces to the skillet. Toss gently to coat everything evenly in the garlic cream sauce. Cook for 1–2 minutes until heated throughout.
08 - Transfer to serving plates and sprinkle generously with chopped fresh parsley. Serve immediately while hot.