Wash and dry all produce. Bring a large pot of salted water to a boil, then add fusilli. After about 8 minutes, add broccoli to same pot. Cook until florets are tender and pasta is al dente, 2-4 minutes. Scoop out and reserve 1/2 cup cooking water, then drain.

Meanwhile, heat a large pan over medium-high heat. Add almonds and stir occasionally until lightly toasted, 2-3 minutes. (TIP: Immediately remove pan from heat if almonds start to burn.) Transfer to a plate, then wipe out and set pan aside while you prep.

Finely chop garlic and sun-dried tomatoes. Heat 1 TBSP butter and a drizzle of olive oil in same pan over medium-high heat. Add garlic and a pinch of chili flakes (save the rest for steps 5 and 6). Cook, stirring, until fragrant, about 1 minute.

Add flour to same pan and stir until lightly toasted, about 30 seconds. Stir in sun-dried tomatoes and milk. Season with salt and pepper. Bring to a gentle boil, then immediately reduce heat to medium-low. Simmer until slightly thickened, 1-2 minutes. Meanwhile, pick basil leaves from stems and roughly chop.

Add sour cream to pan with sauce and stir until well-combined. Stir in fusilli and broccoli. Add just enough pasta water to coat everything in a loose sauce (start with 1/4 cup and add more from there). Season with salt and pepper. (TIP: Give the sauce a taste and season with more salt, pepper, or chili flakes as desired). Add half the Parmesan and half the basil. Stir until everything is well-combined.

Divide pasta between bowls. Sprinkle with almonds and remaining Parmesan and basil. Garnish with additional chili flakes to taste.