Rinse and chop broccoli.
Grate cheddar or Monterey Jack cheese.
In a microwave-safe bowl, add broccoli and just enough water to cover half way. Heat in microwave until bright green and tender, about 6–8 minutes.
Cook pasta following package directions. Drain in a colander and set aside. While pasta is cooking, make cheese sauce.
In a small pot over medium heat, heat milk. When hot, remove from heat. Cover to keep warm.
In a large pot over medium heat, melt butter. Add flour. Whisk with a fork, stirring constantly.
Slowly add the warm milk. Stir constantly with a rubber spatula, until sauce thickens. Sauce should be thick enough to coat the back of a spoon.
Stir in salt and black pepper. Add cream cheese, grated cheese, and broccoli. Stir until grated cheese is melted. Remove from heat.
Add macaroni to cheese sauce. Stir to coat.