Preheat oven to 325.
Bring 5 cups of water to a boil over high heat.
Add dry pasta and 1/4 tsp salt.
Cook for 6-7 minutes.
Remove from heat, drain and rinse in cold water. Return to pot and set aside.
Heavily grease a large 9x13" baking dish with butter and set aside.
Combine cheeses and mix well. Set aside.
Melt remaining butter in a large saucepan over medium heat.
Add flour, whisk to blend and continue whisking for about 2 minutes.
Gradually add in the milk and half and half, whisking constantly. Sauce should remain just below a simmer (if you stop whisking you see an occasional bubble).
Add remaining salt, pepper, paprika, onion powder and garlic powder.
Whisk to blend and continue whisking and cooking until sauce thickens (about 2 minutes).
Remove from heat.
Divide cheese in half.
Gradually add half of cheese to pan stirring constantly until melted and smooth.
Add cheese sauce to cooled pasta until it is well coated with the cheese.
Pour half of the macaroni and cheese into the prepared dish.
Divide remaining cheese in half.
Top with half of remaining cheese.
Add remaining macaroni and cheese to dish.
Top with remaining cheese.
Bake until bubbly and golden, about 35 minutes.