• Boil the pasta in a large pasta pot to an al dente texture, according to the package directions.
• For variety #1, you’ll need the full pound of pasta. For the other two varieties, just 4 ounces of pasta, unless you plan to multiply those recipes by 4.
• Drain the pasta, return it to the pasta pot and toss it with olive oil to prevent it from sticking together. Cover the pasta pot and set it aside.

Make ahead option

• You can place the cooked pasta in a large bowl, cover it with plastic wrap and leave it out at room temperature for up to 8 hours before proceeding with the recipe.

For a roux-based sauce

• In a medium-sized, heavy-bottom saucepan, place the butter and medium heat until it’s melted. Add the flour blend and stir to combine well. The mixture will clump at first, and then smooth.
• Cook the roux over medium heat, stirring constantly, until the mixture has just begun to turn a very light brown color (about 2 minutes).
• Add the evaporated milk to the roux very slowly, stirring constantly to break up any lumps that might form. Add 2 cups of milk, and whisk to combine well.
• Bring the mixture to a simmer and continue to cook, stirring occasionally, until thickened and reduced by about one-quarter (about 7 minutes). The sauce should coat the back of a spoon.
• Remove the saucepan from the heat, add the grated cheese and mix to combine with a silicone spatula or wooden spoon. Add salt and pepper to taste, and the remaining milk a bit at a time if you like a thinner cheese sauce.
• Pour the hot cheese sauce over 4 ounces of the cooked pasta, and stir carefully to coat without breaking the pasta. Serve immediately.

Without a gf flour blend

• In a small saucepan, place the milk over very low heat. Bring to a simmer, whisking very frequently. Continue to cook until the milk just begins to reduce (about 3 minutes).
• Toss the 3 ounces of shredded cheddar in the cornstarch, remove the saucepan from the heat, and add the cheese and starch to the hot milk. 
• Mix to combine. Tear the cheese slices into about 4 pieces each, and add them to the mixture, too. Mix until smooth.
• If necessary to melt all the cheese, return the saucepan to the stovetop over very low heat, mixing constantly. Add salt and/or pepper to taste, and add to 4 ounces of cooked pasta. Serve immediately.

With powdered cheese

• In a small saucepan, place the milk and then the dehydrated cheese. Whisk until very smooth. The powder will resist combining at first.
• Add the butter, and place the mixture over medium-low heat. Cook, whisking frequently, until the butter is melted.
• Cook until the mixture begins to simmer, still whisking frequently. Cook briefly, until the mixture is creamy and slightly thickened.
• The sauce should coat the back of a spoon. Add salt and/or pepper to taste. Add 4 ounces of cooked pasta, toss to coat and serve immediately.