Steps

bring a pot of salted water to a boil and cook the pasta

while pasta is cooking, start cooking the bacon

once the bacon fat has rendered, add the mushrooms and garlic and saute until the garlic is fragrant and the mushrooms are cooked

in the same pan make a bechamel but with the bacon fat in place of the butte. Mix in the flour so everything is coated and then add the milk

add the soy sauce and mix in well

add the spaghetti into the sauce, mix well to coat and season with salt and pepper