Bring a large pot of salted water to a rolling boil. Cook pasta according to package directions until al dente, about 8-10 minutes. Reserve 1 cup of pasta water before draining. Set drained pasta aside.

While pasta cooks, heat a large skillet over medium-high heat. Add oil, then add thinly sliced beef. Season with salt and pepper and cook until browned and cooked through, about 3-4 minutes. Remove beef from skillet and set aside on a plate.

In the same skillet, melt butter over medium heat. Add chopped onion and cook until softened and translucent, about 3 minutes. Add minced garlic and cook for 1-2 minutes until fragrant and golden, stirring frequently.

Pour chicken broth into the skillet to deglaze, scraping up any flavorful brown bits from the bottom of the pan. Add heavy cream and bring mixture to a gentle simmer.

Stir in grated Parmesan cheese and let the sauce simmer and thicken slightly, about 3-4 minutes, stirring constantly. Keep heat at medium-low to prevent curdling.

Add cooked beef back into the skillet, followed by the drained pasta. Toss everything together until pasta is evenly coated in the creamy sauce. Add reserved pasta water, a little at a time, if sauce needs to be loosened.

Serve immediately, garnished with fresh parsley or basil and an extra sprinkle of Parmesan cheese.