Cook pasta according to directions, drain, reserving 1 cup of cooking water.
While pasta is cooking, cook sliced bacon in a large pan until lightly crispy, remove to paper towel lined plate.
Add mushrooms, cook for about 5 minutes over medium heat, until mushrooms have softened.
Add white part of scallions and garlic, cook for about 30 seconds.
Stir in ½ cup of pasta cooking water, butter, soy sauce, dashi powder and miso paste to mushroom/scallions/garlic.
Add pasta and reserved bacon, stir to combine, add more pasta water if needed, to get your desired consistency.
Transfer to a large bowl, or individual servings.
Garnish with green scallions and grated cheese.
