Sauté mushrooms with butter and garlic in a pan until soft and fragrant then set aside.
In a pot, bring water to a boil and cook noodles for 2 minutes then strain and set aside.
While the noodles are cooking, in the same pan, add the reserved ramen water, ½ miso soup packet, and butter over medium heat. Mix until butter is melted, and soup is dissolved.
Carefully add the noodles to the sauce and mix until the noodles are evenly coated.
Turn off and remove from heat, add cheese and mix until evenly combined.
Transfer the noodles to a serving dish and garnish with prepared mushrooms, furikake, and green onions.