Bring a pot of salted water to a boil over medium-high heat.
Add the pasta. Stir and cook for 8-10 minutes until al dente.
Drain in a colander and rinse thoroughly with cold water (yes, for this recipe, you need to rinse it). Set aside to continue draining. Return the pot to the stovetop.
Heat the butter over medium heat to melt. Add the flour, mustard powder, paprika, onion powder, garlic powder and white pepper. With wooden spoon, stir vigorously to combine the flour and spices with the butter and to cook out the flour flavor, toast the spices and to create a roux.
Switch to a whisk. Slowly pour in the milk while simultaneously whisking to incorporate and prevent clumps. Continue to whisk until the béchamel sauce is thickened and coats the back of a spoon, 8-10 minutes.
Increase the heat moderately to speed up the process, but do not boil. Season with salt.
Add the cheese and whisk to combine and melt.
Add the pasta into the pot and stir until evenly coated.
Season to taste. Serve immediately. Sprinkle with chives, a dash of paprika or other toppings as desired. Let your palate guide you.