Cook and drain your pasta according to packet instructions and set aside.
Preheat oven to 180C/350F.
In a pot over medium heat, melt your butter. Add in the miso paste and melt it into the butter, let it get a little toasty and fragrant, around 1-2 minutes. Add in your spices and toast for another 1-2 minutes.
Add in the plain flour and cook out the floury taste for 1-2 minutes. While whisking, slowly add in your milk - stir constantly to avoid lumps. You can add more or less milk to get to your desired texture. Add your brie cheese and 2/3rd of your cheddar and colby jack/mozzarella. Stir to melt the cheese and add in your mustard. Season if needed but the cheeses are already salty!
Add the drained pasta into your cheese sauce and stir well to combine. Transfer to a baking dish, top with the remaining cheese and bake for 20 minutes and then broil for 5 mins or until the cheese is melted and golden brown.
