The ultimate comfort food, Hamburger Casserole is what home cooking is all about.
Cook the pasta according to package directions, minus two minutes. Drain and return to pot away from heat. Set aside.
In a large skillet over medium heat, heat the olive oil until shimmering. Add the onion and cook until softened and translucent. Add the beef and cook thoroughly, breaking up the meat into crumbles with a wooden spoon. (If your meat was fatty, drain it now.)
Pour over the cooked pasta.
Bake for 25 to 30 minutes at 350°F or until bubbly.