Instructions: 

1. Preheat oven to 400°F. 
2. Cook pasta in a large pot of boiling water, stirring occasionally, until al dente, about 10-12 minutes. Drain, reserving 1/2 cup pasta water. Set aside. 
3. Meanwhile, heat 1 Tbsp. butter in a skillet over medium heat. Sauté mushrooms until browned, about 5–6 minutes. Add garlic and cook 1 minute.
4. In a saucepan, melt remaining butter. Whisk in flour and cook 1 minute. Slowly whisk in milk until smooth and slightly thickened.
5. Stir in miso paste, Dijon, black pepper, Gruyère, cheddar, Parmesan, and cooked mushrooms. Cook over low heat until melted and creamy, about 3-5 minutes.
6. Add cooked pasta, adding a splash of pasta water, if needed, to loosen.
7. Transfer to a baking dish. Top with panko and extra Parmesan. Bake for 15–20 minutes until golden and bubbling. Let rest for 5-10 minutes to cool. 
8. Plate pasta and garnish with chives and extra Parmesan. Serve and enjoy!