Place macaroni in boiling salted water and cook according to packet instructions then drain.
While the macaroni is cooking place skimmed milk and corn flour mixture into skillet and heat gently stirring constantly until white sauce thickens then season to taste.
Gradually stir cheese into white sauce until completely combined and no longer lumpy. Then add the chilli powder (tasting to preferred level of heat).
Add drained macaroni to the cheese sauce, give it a stir until well combined then bake in the oven for 10 – 15 minutes.