Cook pasta as directed on package. Drain and spread out on a foil-covered cookie sheet to allow pasta to cool and dry completely.
In a sauce pan over medium heat, melt butter. Add flour and whisk for 1 minute, or until flour and butter are completely blended and smooth.
Add milk and salt and continue to whisk until sauce begins to thicken. Remove from heat and add garlic powder, and dry mustard, whisking until completely blended.
In a mixing bowl, whisk egg yolks until they become light yellow and a little foamy.
Slowly add a little of the flour sauce to the eggs to temper the eggs. Whisk constantly and slowly add the remaining flour mixture to the yolks. Continue to whisk until all sauce is incorporated into the yolks. Stir in cheddar cheese and heat over low heat until cheese is melted. Set aside.
Using a stand mixer, or a small hand mixer, whip egg whites and cream of tartar on high speed until egg whites have tripled in size and form stiff peaks. Using a rubber spatula, gently fold egg whites into cheese mixture.
Add pasta in bowl with egg mixture and mix to coat all pasta evenly.
Coat 5 8oz. ramekins with butter flavor cooking spray. Add equal amounts of parmesan cheese to coat the bottom and sides of the ramekins, and shake out the excess cheese. Fill with equal amounts of pasta.
Place ramekins on a cookie sheet, and bake for 20-22 minutes, or until tops have puffed up and are a golden color.