Boil salted water, and add in the macaroni. Cook until al dente, and drain. Do not rinse.
Cook the Broccoli
Microwave the broccoli for about 3 minutes until mostly warm. Some cold spots are fine.
Four Cheese Broccoli Mac
Preheat the oven to 375°F. Lightly coat a 1 quart casserole with cooking spray.
Melt butter in a skillet with high sides. Add in minced onions, and stir until nearly golden (about 2 to 3 minutes).
Sprinkle flour over onions and whisk to incorporate. Cook an additional 1 to 2 minutes.
Slowly drizzle in chicken broth and milk while continuing to whisk. Bring to simmer for 5 minutes to thicken.
Reserve ¼ cup of cheese mix to sprinkle on top. Turn off the heat and add cheese. Whisk until smooth. Season with salt and pepper.
Combine cooked macaroni, broccoli, and cheese sauce in the oiled casserole dish. Sprinkle reserved cheese mix on top, and lightly spritz with a little cooking spray.
Bake for 15 minutes. Turn the oven to Low Broil for 3 minutes until the cheese on top begins to brown. Remove and let it cool for 10 minutes before serving.