Boil pasta in salted water until al dente. Reserve ½ cup of pasta water and drain the rest.
In a large skillet, melt butter over medium heat. Add scallion whites and mushrooms. Cook for 3–4 minutes until soft.
Stir in chopped kimchi and sauté for another 3–5 minutes until fragrant and lightly caramelized.
Lower heat, add cream, and simmer for 2–3 minutes. Season with salt and pepper to taste.
Add the cooked pasta and a splash of reserved pasta water. Toss until the sauce is creamy and coats the noodles. Stir in scallion greens and more kimchi juice if desired.
Plate and top with grated parmesan and a crack of black pepper.
