- Preheat oven to 350F.
- Cook macaroni according to package directions.
- Dissolve bouillon cubes in boiling water; set aside.
- Combine corn starch and milk in a medium saucepan.
- Add dissolved bouillon cubes, onion, garlic powder, black pepper and cayenne pepper.
- Stirring constantly, bring to a boil; boil and stir for 1 minute.
- Remove from heat.
- Gradually stir in cheeses until melted.
- Add cooked pasta and broccoli.
- Stir until blended.
- Pour mixture into a greased 2-quart casserole dish; top with desired topping.
- Sprinkle with paprika, if desired.
- Bake 20 to 30 minutes or until brown and bubbly.
Broccoli can be quickly thawed by adding to hot pasta water immediately before straining macaroni.