Step 1

Bring a large pot of salted water to a boil. Add the macaroni and cook for 20 minutes, until the macaroni is very soft and plump. Drain the macaroni in a colander and set aside. Do not rinse it with water. If the pasta is cooked before the cheese sauce is finished, toss it with a little cooking oil to keep the noodles from sticking together.

Step 2

Meanwhile, make the cheese sauce by melting the butter in a large pot over medium heat. When the butter is bubbly and melted, about 2 minutes, add the flour. Cook, stirring constantly, until the roux is frothy and smells nutty, about 3 to 5 minutes.

Step 3

In a small bowl, combine the water and nonfat dry milk powder and whisk until the powder is incorporated. Slowly whisk the milk mixture into the roux and bring the mixture to a simmer over medium heat. Cook for 10 minutes, until the liquid has thickened.

Step 4

Place the egg yolk in a small bowl. Add 1/2 cup of the hot milk to the egg yolk, whisking as you add to keep the yolk from scrambling. Add a second 1/2 cup of hot milk, whisking until it's incorporated, before adding the warm egg-milk mixture back to the pot.

Step 5

Remove the pot from the heat. Working quickly to keep the milk from cooling down too much, add the cheese one handful at a time, starting with the torn American cheese and moving on to the grated cheeses after the American is fully incorporated. Stir constantly until the cheese is melted before adding the next handful of cheese.

Step 6

When all the cheese is added and incorporated, stir in the salt, paprika, turmeric, and annatto.

Step 7

Pour the cheese sauce over the cooked macaroni and stir gently to combine. Portion the mac and cheese into individual bowls. Top with additional grated cheddar cheese and melt the cheese under the broiler, if desired.