Bring a large pot of heavily salted water to a rolling boil over high heat, using approximately one tablespoon of salt per quart of water.

Add the spaghetti to the boiling water and cook according to package directions minus two minutes, stirring occasionally, until pasta reaches al dente texture.

While pasta cooks, heat extra virgin olive oil in a large skillet over medium heat until the oil shimmers.

Add sliced cremini mushrooms in a single layer, letting them sit undisturbed for 2-3 minutes to develop golden-brown caramelization.

Stir mushrooms and continue cooking for 4-5 minutes until they release moisture, become tender, and develop rich brown color.

Push cooked mushrooms to the sides, add minced garlic to center, and stir constantly for 30 seconds until fragrant and golden.

Before draining pasta, reserve one cup of the starchy pasta cooking water, then drain the spaghetti in a colander.

Add drained pasta directly to the skillet with mushrooms and garlic, tossing everything together with tongs to combine.

Add reserved pasta water gradually, starting with one quarter cup, tossing continuously to create a silky sauce.

Remove pan from heat, add freshly grated parmesan cheese and chopped fresh parsley, tossing until cheese melts.

Season with coarse sea salt and freshly ground black pepper to taste, adding red pepper flakes if desired.

Serve immediately in warmed pasta bowls, garnishing with additional parmesan cheese, parsley, and a drizzle of olive oil.