1. Bring a large pot of salted water to a boil. Add 2 cups dry elbow macaroni and cook until just al dente, about 7–8 minutes. Drain and set aside.

2. In a large skillet, heat 1 tablespoon olive oil over medium heat. Add 1 pound ground beef and cook, breaking up with a spoon, until no longer pink. Stir in 1 medium diced onion and 2 minced garlic cloves. Cook until onion is soft, about 3–4 minutes. Drain excess fat.

3. Stir in 1 can (15 oz) tomato sauce and 1 can (14.5 oz) drained diced tomatoes. Add 1 teaspoon salt, 1/2 teaspoon pepper, and 1 teaspoon Italian seasoning. Simmer for 3–4 minutes.

4. Preheat oven to 350°F (175°C). In a large bowl, combine cooked macaroni, beef mixture, and 1 1/2 cups shredded cheddar cheese. Mix well.

5. Pour mixture into a greased 9×13-inch baking dish. Top evenly with remaining 1 1/2 cups cheddar cheese.

6. Bake for 20–25 minutes, until cheese is melted and casserole is bubbly. Rest 5–10 minutes before serving.