Macaroni and Beef Casserole

Name: Macaroni and Beef Casserole
Ingredients: 1 pound elbow macaroni; 3 tablespoons extra-virgin olive oil, plus more for tossing; 1 onion, finely chopped; 1 green bell pepper, cut into 1/4-inch dice; 2 pounds ground beef; 2 teaspoons ground cumin; 2 tablespoons all-purpose flour; 1 (15-ounce) can crushed tomatoes; 1/2 cup chicken stock or low-sodium broth; 1/4 cup heavy cream; 1/4 cup chopped parsley; 6 ounces sharp cheddar cheese, shredded (2 cups), divided; Kosher salt; Freshly ground black pepper; 1/3 cup panko; 3 scallions, thinly sliced