Wash 1 head of broccoli and cut it into florets
Steam or boil the broccoli until tender, about 4 to 5 minutes
Drain the broccoli well
Melt 2 tablespoons of butter in a saucepan over medium heat
Stir in 2 tablespoons of flour and cook for 1 minute
Slowly whisk in 1 cup of milk until smooth
Cook, stirring, until the sauce thickens
Add 1 to 1 1/2 cups of shredded cheese and stir until melted
Season with salt and pepper
Add the broccoli to the cheese sauce and stir to coat
Serve warm