Cook and drain macaroni.
Preheat oven to 375F. Grease a 2-quart casserole dish.
Combine cornstarch, salt, mustard and pepper in medium saucepan.
Stir in evaporated milk, water, and butter. Cook over medium-heat, stirring constantly, until
mixture comes to a boil.
Boil for 1 minute. Remove from heat.
Stir in 1 1/2 cups cheddar cheese & Monterey Jack until melted. Add macaroni;
mix well. Pour into pre
pared casserole dish. Top with remaining cheese.