Cook the pasta according to package directions. Drain and set aside.
Steam or boil broccoli until very soft (about 5–7 minutes). Drain.
Blend the “surprise” sauce: Add broccoli + milk to a blender and blend until smooth and creamy.
In a large pan, melt butter over medium heat. Whisk in flour and cook 1 minute.
Slowly whisk in the broccoli-milk blend until smooth and slightly thickened.
Stir in cheddar, parmesan, garlic powder, salt, and pepper until melty and creamy.
Add cooked pasta and stir until fully coated.
Serve warm and pretend you didn’t just successfully hide a vegetable.