Heat olive oil in a large skillet over medium heat. Add diced onion and cook until translucent and aromatic, about 3-4 minutes.
Add the ground beef to the skillet and cook, breaking it apart with a spoon, until browned and cooked through, about 6-8 minutes. Season with salt and pepper.
Stir in the minced garlic and cook for another minute until fragrant.
Pour in the tomato sauce and let it simmer for a few minutes until it slightly thickens and the flavors meld.
In the meantime, cook the noodles in boiling water until al dente, about 8 minutes. Drain and set aside.
Combine the cooked noodles with the beef mixture in a large bowl, mixing well to coat all the noodles evenly.
Transfer half of the noodle-beef mixture into a greased baking dish, spreading it evenly.
Sprinkle half of the shredded cheese over the first layer, then add the remaining noodle mixture on top.
Top with the remaining shredded cheese, distributing it evenly across the surface.
Bake in a preheated oven at 375°F (190°C) for about 20-25 minutes, until the cheese is melted and bubbly, with golden edges.
Remove from the oven and let it rest for a few minutes before serving. Slice and enjoy this cheesy, savory casserole that's perfect for comfort food cravings.
