No-Bake Macaroni and Cheese
Bring a large pot of water to a boil. Cook pasta for 4 mins. Add frozen or fresh broccoli and continue cooking, stirring occasionally, until pasta and broccoli are just tender, 4 to 5 minutes more.
Heat 1-1/2 cup of milk in a medium pot over medium-high heat until just simmering. Whisk the remaining 1/4 cup milk, flour, garlic powder, salt and pepper (if using) in a small bowl until combined. Add the flour mixture to the simmering milk, return to a simmer and whisk until thickened, 2-3 minutes. Remove from heat and whisk in cheddar, parmesan and mustard until cheese is melted.
Drain the pasta and broccoli and add to the cheese sauce, Return to heat and stir until heated through, about 1 minute.