1-First, preheat your oven to 400°F (204°C) and grease a 9×13-inch (23×33 cm) baking dish to prevent sticking. This step sets the stage for even cooking and helps the casserole come out just right. Make sure to have all your ingredients measured and ready, like the 1 pound of uncooked penne pasta and the lean ground beef, to avoid any last-minute rushes.

2-Next, boil salted water in a large pot and cook the 1 pound of penne pasta for about 10 minutes, leaving it slightly undercooked. This ensures the pasta doesn’t get too soft when baked later, maintaining a nice texture in the final dish. Once done, drain the pasta and set it aside while you move on to the meat mixture. This part is quick and helps build the base of your casserole.

3-In a skillet, heat 1 tablespoon of olive oil over medium-high heat and add the 1 pound of chopped onion and lean ground beef. Sauté for about 10 minutes, breaking up the meat as it cooks until it’s fully browned. Then, add the minced garlic and cook for another minute or so, and drain any excess fat if needed to keep things light. For added flavor, stir in 1.5 cups of marinara sauce, and season with salt and pepper to taste, heating everything through for a rich, savory blend.

4-Now, transfer the drained pasta to your greased baking dish and pour the beef sauce mixture over it, tossing everything together evenly. Spread the mixture out flat and top it with 1.5 cups of shredded cheddar cheese for a gooey finish. Bake uncovered for 10 minutes or until the cheese melts perfectly, and if you like, broil for a few extra minutes to get that golden brown top. This step brings all the flavors together in one cozy bake.