Preheat your oven to 180°C (350°F).

Cook the elbow macaroni in a large pot of salted boiling water until just al dente (about 7 minutes). Drain and set aside.

Heat olive oil and butter in a large skillet over medium heat. Add chopped onion and cook for 3 minutes until softened. Add garlic and cook for another 1 minute.

Add ground beef to the skillet. Cook, breaking it up with a spoon, until browned and cooked through (about 6 minutes). Drain excess fat if necessary.

Stir in the diced tomatoes, tomato sauce, oregano, basil, salt, and black pepper. Let it simmer for 5 minutes to blend the flavors.

Remove from the heat and mix in the sour cream. Add the cooked macaroni and half of the shredded cheddar cheese, stirring to combine.

Transfer the mixture into the greased 9x13 inch baking dish. Smooth out the top, then sprinkle with the remaining cheddar cheese.

Bake uncovered for 20 minutes until the cheese is melted and bubbly.

Let the casserole sit for 5 minutes before serving.