Bring a large pot of lightly salted water to a boil. Cook spaghetti in the boiling water, stirring occasionally, until tender yet firm to the bite, about 12 minutes. Drain.
Meanwhile, place mushrooms in a dry skillet over medium heat. Cook until they begin to brown and release moisture, 3 to 5 minutes. Add oil and garlic. Fry until softened, about 3 minutes more.
Beat eggs together in a bowl. Add 1/2 the Parmesan cheese. Mix well and stir into cooked mushroom mixture.
Serve the pasta topped with mushroom sauce and remaining Parmesan cheese.
