Preheat oven to 400F. Fill a Stockpot fitted with a Pasta Insert with water and bring to a boil. Season heavily with salt (it should taste like the ocean) and cook macaroni until just al dente. Drain and set aside.

Melt 4 Tbsp. butter in a 5 QT Saucier over medium heat. Add garlic and cook for about 30 seconds until fragrant,  stirring quickly to keep it from burning.

Sprinkle in flour and whisk to create a roux. Stir constantly until roux turns golden brown and smells nutty, adjusting heat if necessary to avoid burning the garlic, 4–5 minutes.

Add creamy shio koji and whisk to combine. Slowly stream in the milk, whisking as you incorporate it. Continue whisking until mixture comes to a boil, 5–8 minutes, to fully activate the roux.

Remove from heat and slowly whisk in cheese until melted. Season with salt and pepper to taste.

Return the macaroni to the Stock Pot and pour in the cheese sauce. Stir to combine and transfer into Oval Baking Dish.

To make the topping, melt remaining 2 Tbsp. butter in a Butter Warmer over medium-low heat. Toss together breadcrumbs, melted butter, parmesan, chili pepper, and dried herbs in a small bowl.

Sprinkle topping over macaroni and cheese, place on top of a Sheet Pan to catch any drips, and bake until golden brown, about 10 minutes.