Preheat oven to 425 degrees F. Oil a 2-quart baking dish.

Bring large pot of salted water to a boil. Add the noodles and cook according to package directions (al dente). Drain and put in the prepared baking dish.

Meanwhile, heat the olive oil in a large skillet over medium-high heat. Add ground beef and cook, stirring, until no longer pink, about 4 minutes. Add bell peppers and scallions and cook until crisp-tender, about 3 minutes.

Make a space in the pan, add tomato paste and toast for a minute. Sprinkle with the Italian seasoning and 1/4 tsp salt. Add the diced tomatoes, stir and bring to a simmer. Cook until slightly thickened, about 2 minutes.

Pour the beef mixture over the noodles and sprinkle with the grated Cheddar. Bake on the middle rack until e cheese is melted and he edges are bubbling, 15 to 20 minutes.

Let stand for 10 minutes before serving.