reduced to a glaze, about 10 minutes. Add half-and-half and simmer until beginning to thicken, about 5 minutes. Remove from heat (can be prepared 3 days ahead, cover and refrigerate.) Add pasta to large pot of boiling salted water. Cook until tender but still firm to bite, stirring occasionally. Meanwhile, rewarm mushroom sauce over medium-low heat. Drain pasta. Add to sauce and stir until coated. Mix in 2/3 cup parmesan. Season with salt and pepper. Transfer to plates. Sprinkle with parsley. Serve immediately with garlic toasts, passing additional parmesan separately (see recipe for garlic toasts).