Gather the ingredients.
Cook the pasta in a large pot of salted water to barely al dente, about 1 to 2 minutes under the recommended time. Reserve 1/2 cup of the pasta water. Drain the pasta and reserve.
In a large, heavy-bottomed pot, heat the butter over medium heat, stirring to melt. Add the flour and stir to incorporate into the butter to make the roux. Cook for 1 minute, or until golden brown, to cook off the flour taste.
Whisk in the evaporated milk and the heavy cream. Cook for another 1 to 2 minutes over medium heat or until the mixture has warmed through. Add the cheddar cheese spread and cheese powder to the milk. Slowly, add the shredded cheddar cheese, continuously whisking. Stir until you have a homogeneous sauce. Do not let the sauce boil.
Add the cooked pasta into the sauce and mix well. If the sauce is too thick, add about 1/4 cup of the pasta water. Add salt and pepper to taste. Serve immediately.