Preheat Oven To 400 Degrees F (200 Degrees C). Fill A Large Pot With Lightly Salted Water, Bring To A Rolling Boil Over High Heat. Stir In The Bow Tie Pasta And Return To A Boil. Boil Pasta, Stirring Occasionally, Until Cooked Through But Still Firm To The Bite, About 12 Minutes. Drain Well. Cook And Stir Ground Beef And Onion In A Large Skillet Until Beef Is No Longer Pink, About 5 Minutes. Drain Fat. Stir In Pasta Sauce And Bring To A Boil. Reduce Heat To Simmer. Stir Cooked Pasta And Half Of The Mozzarella Cheese Into The Sauce; Toss To Combine. Transfer To A 2-Quart Baking Dish. Top With Remaining Mozzarella And Parmesan Cheese. Bake In Preheated Oven Until Lightly Browned And Bubbly, 15 To 20 Minutes.