Pat the steak dry with paper towels. Season both sides generously with kosher salt, freshly ground black pepper, a light dusting of garlic powder, and smoked paprika. Let it rest at room temperature for 10–15 minutes.

Bring a large pot of salted water to a boil. Cook tortellini until al dente according to package instructions. Before draining, reserve 3/4 cup of the pasta water.

Heat a large skillet over high heat until very hot. Add 2 tablespoons olive oil. Sear the steak 2–4 minutes per side, depending on thickness and desired doneness. Transfer steak to a cutting board and let rest 5–10 minutes.

Reduce heat to medium. In the same skillet, add 4 tablespoons unsalted butter. Once melted, add minced garlic and sauté 30–60 seconds until fragrant but not browned.

Pour in 1 cup heavy cream and 3/4 cup whole milk. Bring to a gentle simmer and cook until the sauce thickens slightly, about 3–5 minutes.

Stir in 1 1/4 cups Parmesan until melted and the sauce is smooth. If the sauce is too thick, whisk in reserved pasta water until you reach a silky consistency.

Slice the rested steak thinly across the grain. Add drained tortellini and sliced steak to the skillet. Toss gently to coat everything in the cream sauce.

Taste and adjust seasoning with salt, cracked black pepper, and a pinch of red pepper flakes if using. Garnish with chopped parsley and serve immediately.