Soak dried mushrooms in 1 3/4 cup of hot tap water. Remove mushrooms from water after 20 minutes(reserve liquid) and slice mushrooms.
Add butter to saucepan over medium heat, once butter has melted add onions, mushrooms and salt and cook until onions are translucent. Add the rice and toss until all of the grains are coated with the butter. Add the reserved mushroom water, cover and cook until the water is absorbed and the rice is tender, about 15 to 20 minutes. Turn off the heat and allow to sit covered for 5 to 10 minutes. Add parsley and fluff with a fork.