01 - Bring a large pot of salted water to a boil. Cook the cheese tortellini according to package directions until tender. Drain through a strainer and set aside.
02 - Pat the sirloin pieces dry and season generously with salt and freshly ground black pepper. Heat olive oil in a large skillet over medium-high heat until shimmering. Add 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 rest.
03 - Reduce the skillet heat to medium. Add the unsalted butter and let it melt. Sauté the finely chopped shallots and minced garlic, stirring frequently, until softened and fragrant, about 1 minute.
04 - Pour in the heavy cream, stirring to scrape up any browned bits from the bottom of the pan. Bring to a gentle simmer and cook for 2–3 minutes, allowing the sauce to reduce and thicken slightly.
05 - Stir in the grated Parmesan cheese, continuing to stir until fully melted and the sauce is smooth and velvety.
06 - Return the drained tortellini and seared steak to the skillet. Toss gently to coat everything evenly in the garlic cream sauce and heat through, about 1–2 minutes.
07 - Transfer to warmed plates and sprinkle generously with chopped fresh parsley. Serve immediately.