Original recipe yields 4 servings
2 cups whole milk
1 teaspoon kosher salt, or more to taste
1 pinch cayenne pepper
1 pinch dried mustard (Optional)
1 very small pinch ground nutmeg
3 tablespoons unsalted butter, divided
1 cup elbow macaroni
½ cup panko bread crumbs
1 cup freshly shredded sharp Cheddar cheese
1 cup freshly shredded white Cheddar cheese
Bring milk, salt, cayenne, mustard, nutmeg, and 1 tablespoon butter to a simmer in a pot over medium heat. Stir in macaroni. Simmer, stirring occasionally, until firm yet tender to the bite, about 8 minutes. Do not undercook.
Meanwhile, melt remaining butter in a skillet over medium heat. Add bread crumbs and toast until golden brown, 3 to 5 minutes.
Stir cheeses into the cooked macaroni. Reduce heat to low and stir just until melted. Turn off heat, cover, and let sit for 3 minutes. Uncover, stir, and season to taste.
Spoon mac and cheese into warm serving bowls; sprinkle toasted breadcrumbs on top.