Instructions:
- Set a large pot of heavily salted water to boil. Cook the macaroni about a minute shy of the package instructions until al dente. Drain well.
- In a large skillet, melt the Kerrygold Unsalted Butter over medium heat. Sprinkle the flour over the butter and whisk for 1 minute until a paste forms and the mixture begins to bubble but does not brown.
- Gradually whisk in the warmed milk and turn the heat to medium-low as soon as the mixture thickens. Whisk in 1/2 teaspoon salt, 1/4 teaspoon pepper, the nutmeg, and the ground mustard.
- Stir in the cheeses; when thoroughly melted, add the cooked macaroni and stir well to combine.
- Transfer the macaroni mixture to a 9 x 13-inch baking dish.
- In a small bowl, combine the panko, thyme leaves, and remaining salt and pepper. Sprinkle evenly over the macaroni mixture.
- Bake uncovered until the sauce is bubbly on the sides and the panko is browned and crispy on top, about 15 minutes.