1-First, preheat the oven to 400 degrees Fahrenheit and position the rack in the middle. Grease a 9×13 baking dish to make sure nothing sticks later on.

2-Next, boil a large salted pot of water and cook the 1 pound of uncooked penne pasta for 10 minutes, keeping it slightly undercooked to avoid mushiness during baking. In a skillet, heat the 1 tablespoon of olive oil over medium-high heat, then add the 1/2 medium chopped onion and 1 pound of lean ground beef (90% lean or more). Cook for about 10 minutes, breaking the meat apart as it browns, and stir in the 1 clove of minced garlic once the beef starts cooking. Remove any excess fat if needed to keep the dish from getting greasy.

3-Stir in the 1.5 cups of marinara sauce and warm it through, then season with salt and pepper to taste for that perfect flavor. Drain the pasta and pour it into the prepared baking dish. Add the beef mixture over the pasta, toss everything to combine, and spread it evenly. Top with the 1.5 cups of shredded cheddar cheese, and if you want it extra cheesy, stir in an additional half cup of cheese before topping. Bake uncovered for 10 minutes until the cheese melts, and broil for a few minutes to brown it if you like. Serve right away for the best taste, making this one of the top ground beef casserole meals you can prepare.