Boil the macaroni noodles (or pasta of your choice) in lots of salted water until they are very al dente. I shave 2-3 minutes off the cooking time.
Drain the noodles and rinse them under cold water until they are cool to the touch. This stops the noodles from continuing to cook.
Melt the butter in a medium-size pot. Turn off the heat. Using a whisk, slowly add the flour and whisk well until it is all blended in. Turn the heat back to medium, and continue whisking while the butter-flour mixture cooks for a minute.
Meanwhile, heat the milk and cream in a saucepan or in the microwave until it is hot but not scalding.
Pour the hot milk/cream in a thin stream into the butter-flour mixture, all while whisking.
When the milk is all in, continue cooking the sauce over medium heat while whisking until it boils and thickens. Turn off the heat.
Add the mustard powder, onion powder, and garlic powder. Whisk it in well.
Add the cream cheese, cheddar and gouda to the sauce and stir to melt and combine. Turn the heat up for a minute or two if your cheese isn't melting well, but don't boil the sauce or it could burn on the bottom of your pot.
Check the sauce for salt and pepper. Add 1/4 teaspoon of white pepper and up to 1/2 teaspoon of salt if necessary.
Combine the cooked pasta with the sauce and load it into a half-sheet size foil pan or a pan large enough to hold all the noodle-y goodness.