Bring a large pot of salted water to boil. Heat oil in a large skillet over low heat and add the garlic, cooking gently for a minute or so. Add the mushrooms , season with salt and pepper, then cover and cook over low heat, 5-8 minutes until soft. They should give out enough moisture to cook themselves. In the meantime, cook the bucatini until al dente. When the mushrooms are finished, add lemon juice and parsley, then stir in the drained pasta. Mix thoroughly and finish with a splash of olive oil.