Preheat oven to 375°
Cook pasta al dente. Drain, rinse with cold water, set aside.
In a large saucepan, melt butter over medium/low heat.
Whisk flour into butter and continue to whisk for a couple minutes.
While stirring, add half and half, ground mustard, cayenne pepper, salt and pepper.
Bring to a boil and continue stirring until thickened.
Add all three cheeses, except 1 cup of sharp cheddar, which will be used for topping, stir until melted.
Once melted, pour cheese mixture over pasta, stir.
Lightly spray a 3 quart baking dish with non stick spray.
Pour macaroni and cheese into baking dish.
Top with remaining cup of sharp cheddar.
Bake until cheese is bubbly and starting to brown, approximately 30-35 minutes.
Serve hot and enjoy!