2. Bring a large pot of salted water to a boil.
3. In a 2-quart saucepan, whisk the olive oil and flour together over medium heat. Cook until the mixture gives off a "nutty" aroma, about 2 minutes. Slowly whisk in the hot milk and simmer, stirring occasionally, for 5 minutes. Stir in the Parmesan cheese and season with salt and pepper. Set aside.
4. Add the macaroni to the boiling water and cook until the pasta is al dente, about 7 or 8 minutes. Drain the pasta.
5. Pour the macaroni into the prepared casserole dish. Immediately pour the milk mixture over it and stir to combine. Sprinkle the grated cheddar cheese over the top and then sprinkle the breadcrumbs over the cheese.
6. Bake, uncovered, for about 30 minutes or until the edges are bubbling and the top is golden brown. Remove from the oven and let stand for 10 minutes before serving.