Preheat the oven to 350°F.
Bring a large pot of water to a boil and add the pasta. Cook to al dente, then drain and set aside. While the pasta cooks, you can begin the sauce.
Heat a 10-inch oven-safe skillet over medium heat. Add the butter and let it melt, then add the mustard powder, onion powder, granulated garlic, and flour. Whisk to combine, forming a thick paste.
Add the milk and cream to the skillet and heat until warm, then add half of the cheese. Stir or whisk to allow it to melt and combine with the milk, then add the remaining cheese, reserving half for later. Continue to heat the sauce until the cheese is fully melted and the sauce is slightly thickened.
Add the drained noodles to the skillet and stir to combine with the sauce.
In a small bowl, combine the panko breadcrumbs, softened butter, parsley flakes, and granulated garlic.
Sprinkle the reserved cheese over the macaroni and then sprinkle the breadcrumbs over top.
Place the skillet in the oven and bake for 15-20 minutes until the sauce is bubbly and the breadcrumbs are lightly toasted.
Remove from the oven and serve immediately.