Bring a large pot of water to a boil and cook the pasta according to package directions. Drain and set aside.

Preheat a large saucepan over medium heat. Melt the butter and then add in the flour. Whisk the butter and flour together until you form a roux. Cook for one minute then pour in the hard apple cider, whisking until all lumps have been smoothed out.

Gradually add in the milk and continue to whisk until the sauce has thickened. Reduce the heat to low and add in the cubed brie and shredded cheese. Continue to stir until all the cheese has melted.

Stir in the Dijon mustard, nutmeg, kosher salt and pepper. Add the cooked pasta to the sauce and gently toss. Garnish with fresh thyme and serve immediately.