To make, spray a 9×13 inch baking dish with non-stick cooking spray. Pour the dry macaroni noodles in the dish with 1 cup shredded cheese and chopped broccoli. Combine and set aside.
Melt butter in a saucepan. Gradually whisk in the flour. The pour the milk and continue whisking. Add in the water and whisk again. Bring to a boil, reduce the heat to a simmer.