Heat the olive oil in a 12-inch skillet over medium heat. Add the diced onion and cook for about 5 minutes, stirring occasionally, until it becomes soft and translucent.

Stir in the minced garlic and cook for 1 minute until fragrant. Add the ground beef, breaking it apart with a wooden spoon. Cook for 6-8 minutes until no pink remains and the beef develops a nice brown crust. Season generously with salt and pepper. Drain excess fat if there is more than 2 tablespoons.

While the beef browns, bring a large pot of salted water to a boil. Add the pasta and cook according to package directions until al dente, usually 8-10 minutes. Before draining, reserve 1/2 cup pasta water, then drain well and set aside.

Pour the vegetable broth into the skillet with the cooked beef and stir to combine, scraping up any browned bits. Add the heavy cream and bring to a gentle simmer. Let it bubble for about 3 minutes, stirring occasionally, until the sauce thickens and becomes bubbly with a glossy sheen.

Remove from heat and stir in the Parmesan cheese until completely melted and smooth. Add the drained pasta to the skillet, tossing gently to coat every piece in the creamy sauce. If the sauce seems too thick, add reserved pasta water one tablespoon at a time. Taste and adjust seasoning as needed. Serve immediately with extra Parmesan on top.