Cook the noodles: Bring a large pot of salted water to a boil, add the uncooked egg noodles and cook until al dente, about 6-8 minutes. Drain and set aside.

Preheat the oven: While the noodles are cooking, preheat your oven to 350°F (175°C).

Brown the beef: In a skillet over medium heat, add ground beef and diced onion. Cook until the beef is browned and the onion is translucent, about 5-7 minutes. Drain any excess grease.

Sauté the garlic: Add minced garlic to the skillet with beef and onion, sauté for 30 seconds until fragrant.

Mix the sauce: In a mixing bowl, combine cream of mushroom soup, cream of cheese or cheddar cheese soup, sour cream, and milk. Whisk until smooth, then stir in Italian seasoning, salt, and black pepper.

Combine ingredients: Add cooked noodles and beef mixture to the sauce, stir gently. Fold in any optional ingredients.

Prepare for baking: Transfer the mixture to a greased 9x13-inch baking dish and top with the first cup of shredded cheddar cheese.

Bake the casserole: Place in the preheated oven and bake for 25-30 minutes until bubbly and golden brown.

Rest before serving: Remove from oven and let rest for 5-10 minutes before serving.