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

Cut broccoli into bite-size pieces if necessary. Trim and thinly slice scallions, separating whites from greens.

Once water is boiling, add cavatappi to pot. Cook, stirring occasionally, until al dente, 9-11 minutes.

Reserve 1 cup pasta cooking water (2 cups for 4 servings), then drain.

While pasta cooks, heat a drizzle of oil in a large pan over medium-high heat. Add broccoli, scallion whites, a pinch of salt, and pepper. Cook, stirring occasionally, until browned and tender, 4-6 minutes. 

Reduce heat to low; stir in white cheddar, cheddar, cream cheese, sour cream, Vidalia onion paste, garlic powder, and ½ cup reserved pasta cooking water (¾ cup for 4 servings). Cook, stirring constantly, until sauce is smooth and slightly thickened, 1-2 minutes. Turn off heat. TIP: If pasta is not done cooking, ladle pasta cooking water directly from pot. Keep broccoli and sauce covered off heat until pasta is finished cooking.

Stir drained cavatappi into pan with sauce until thoroughly coated. Taste and season with salt and pepper if desired. TIP: If pasta seems dry, stir in splashes of reserved pasta cooking water as needed.

Divide pasta between bowls; top with scallion greens and crispy fried onions. Serve.