Put a large pot of water on to boil. When it's bubbling rapidly, add a fat pinch of salt and your pasta. Cook for one minute less than the packet says, stirring occasionally. Drain the pasta.
While your pasta is cooking, make your cheese sauce. Add the butter to a skillet over low heat and let it melt. Then whisk the flour into the melted butter and let it cook for a minute or so until it starts to smell nutty.
Add your milk, about a quarter cup at a time, to the flour and butter mixture, whisking until smooth after each addition. Once all the milk is added, allow the mixture to return to a simmer to thicken.
Then stir in your cheese, pepper, mustard powder, granulated onion, and cayenne.
Once both the pasta and the sauce are finished, fold them together in the skillet.
To make your breadcrumbs, melt the butter in a smal saucepan over medium heat. Add your minced garlic to the butter and let it cook for about a minute until the garlic becomes fragrant.
Off the heat, stir in the breadcrumbs to coat them in the butter, then stir in the parsley, oregano, and chili flakes. Finally, stir in the Parmesan cheese.
Add about half of your breadcrumb mixture to the pasta and stir it through. Transfer your mac and cheese to a casserole or individual dishes on a baking tray. Cover this with the remaining breadcrumbs.
Bake for about 15 minutes or until bubbly and golden brown. Allow to cool for 5-10 minutes before serving.