Cook pasta in a large pot of salted boiling water until al dente.

While pasta cooks, melt two tablespoons butter in a large skillet over medium heat. Add mushrooms to skillet and cook until mushrooms are tender, about 5 minutes.

Sprinkle mushroom with salt and pepper, then add in garlic and shallots. Cook for about 2 minutes or until very fragrant.

Reserve 1 cup of pasta water, then drain pasta and transfer to the skillet. Add in remaining 2 tablespoons of butter and about ½ cup of that reserved pasta water.

Reduce heat to low, and simmer until a nice sauce forms and coats the pasta. Continue adding remaining reserved pasta water if pasta begins to dry out. Remove from heat and serve immediately.