Macaroni-and-Beef Casserole

elbow macaroni

extra-virgin olive oil, plus more for tossing

onion, finely chopped

green bell pepper, cut into 1/4-inch dice

ground beef

ground cumin

all-purpose flour

crushed tomatoes

chicken stock or low-sodium broth

heavy cream

chopped parsley

sharp cheddar cheese, shredded (2 cups)

Kosher salt and freshly ground pepper

panko (Japanese bread crumbs)

scallions, thinly sliced