Bring a large pot of salted water to a boil. Wash and dry produce.

Trim and thinly slice scallions, separating whites from greens.

Heat a drizzle of oil in a large, preferably oven-safe, pan over medium-high heat. Add beef*, scallion whites, salt, and pepper; cook, breaking up meat into pieces, until browned and cooked through, 4-5 minutes. Carefully drain any excess grease from pan.

Add Italian Seasoning and cook, stirring, until fragrant, 30 seconds.

Stir in crushed tomatoes, salt (we used ½ tsp; 1 tsp for 4 servings), and pepper. Bring to a boil, then reduce heat to medium low. Simmer, stirring occasionally, until slightly thickened, 5-6 minutes. 

Once water is boiling, add spaghetti to pot. Cook, stirring occasionally, until al dente, 9-11 minutes. Reserve ½ cup pasta cooking water (1 cup for 4 servings), then drain.

Heat broiler to high.

Add drained spaghetti and ¼ cup pasta cooking water (⅓ cup for 4 servings) to pan with sauce; toss to coat. Taste and season with salt and pepper if desired. TIP: If pasta seems dry, add splashes of pasta cooking water until coated in sauce.

Spread pasta in an even layer in pan, carefully wiping any sauce from the sides (to prevent burning!). Sprinkle mozzarella evenly over the top; broil until cheese is melted and browned in spots, 30-60 seconds. TIP: If your pan is not oven-safe, transfer pasta to a baking dish before adding the cheese.

Garnish with scallion greens; divide between plates or serve family style directly from the pan.