Steam broccoli until crisp-tender, about 4–5 minutes.
While the broccoli is steaming, melt the butter in a medium saucepan over medium-low heat.
Whisk in flour and mustard powder and cook for about 1 minute. Pour in the milk, and whisk constantly until the sauce comes to a bubble and has thickened substantially.
Add cheese in 3 increments, stirring until each addition is completely melted before adding the next.
Season to taste with salt.
Pour this wonderful sauce over the freshly steamed broccoli.
Serve and enjoy!
Notes
Whether you make this recipe with fresh broccoli or frozen, it’s a home run for the entire family!