Prep the ingredients by chopping the onion and mincing the garlic. Measure out the elbow macaroni, tomato sauce, and diced tomatoes.
In a large pot, bring water to a boil, add a pinch of salt, and cook the elbow macaroni until al dente, about 7-8.
In a large skillet, heat oil over medium heat, sauté the onion and garlic until translucent, about 3-4. Add ground beef and cook until browned, then drain excess fat. Stir in tomato sauce, diced tomatoes, oregano, basil, salt, and black pepper, and let simmer for about 5.
In a large bowl, combine cooked macaroni, meat sauce, and sour cream. Mix well and pour into a greased baking dish. Sprinkle shredded cheddar cheese on top.
Preheat oven to 350°F. Bake the casserole for 25-30 until cheese is bubbly and golden brown. Let cool for a few minutes before serving.