Preheat the oven to 400 degrees F (200 degrees C).

Bring a large pot of lightly salted water to a boil. Cook bow tie pasta at a boil, stirring occasionally, until tender yet firm to the bite, about 12 minutes. Drain.

Heat a large skillet over medium-high heat. Add ground beef and onion; cook and stir until browned and crumbly, 5 to 7 minutes. Drain and discard grease. Stir in pasta sauce; bring to a boil. Reduce heat to low; simmer.

Stir cooked pasta and 1/2 mozzarella cheese into sauce to combine; transfer to a 2-quart baking dish. Top with remaining 1/2 mozzarella and Parmesan cheeses.

Bake in the preheated oven until lightly browned and bubbly, 15 to 20 minutes.