Cook the Pasta: Bring a large pot of salted water to a boil and cook the pasta according to the package instructions until al dente. Set aside approximately one cup of pasta water before draining the noodles.

Cook the Mushrooms: In a large skillet, warm the olive oil over medium heat. Add the sliced mushrooms and cook until they release their moisture and begin to brown (about 5-7 minutes). Set aside.

Sauté Aromatics: In the same skillet, melt the butter over medium heat. Add the minced garlic and diced shallot, sautéing until fragrant and translucent (about 2-3 minutes).

Make the Sauce: Lower the heat and add the heavy cream to the skillet, stirring gently to combine. Stir in the miso paste, allowing it to dissolve into the cream. Slowly add in the reserved pasta water, stirring continuously until you achieve your desired sauce consistency.

Combine Pasta and Sauce: Toss the cooked pasta in the skillet with the sauce, ensuring it's evenly coated. Mix in the Parmesan cheese until it melts and the sauce becomes creamy. Adjust the seasoning with salt and pepper to your liking.

Serve and Garnish: Serve the creamy miso pasta hot, garnished with roasted nori strips and a sprinkle of red pepper flakes for a touch of heat.