Preheat the oven to 350°F.

Bring a large pot of water to a boil. Add 1–2 tablespoons of salt. Add the pasta and cook according to the package directions for al dente (or the lowest suggested cooking time). Drain well and set aside.

While the pasta cooks, melt the butter in a large pot over medium heat.

When the butter is melted and foamy, add the flour. Cook for 2 minutes, stirring frequently.

Add the milk while stirring briskly. Continue stirring until the sauce is smooth.

Add the Worcestershire sauce, 1 teaspoon salt, black pepper, mustard powder, garlic powder, and onion powder. Stir well to combine.

Let the sauce come to a simmer over medium heat, about 6–8 minutes, stirring occasionally. Once it simmers, reduce the heat to medium-low or low.

Continue cooking the sauce for 2–3 minutes at a gentle simmer, stirring often. Do not leave it unattended, and do not increase the heat—it may scorch.

Remove the pot from the heat. Stir the sauce a few times and let it stop simmering before adding the cheese.

Add the cheese a handful at a time, stirring well after each addition until fully melted.

Add the cooked macaroni to the cheese sauce and stir to combine. Taste and add more salt if needed. (As a reference, we added ½ teaspoon to ours.)

Portion the mixture into ovenproof ramekins, baking tins, or bowls. We used 6-ounce ramekins. Place them on a baking sheet to catch any drips.

Bake for 25–30 minutes, or until bubbly around the edges and golden on top.

Let cool slightly to help them set. Garnish with chopped parsley, if desired, and serve.