In bowl, soak mushrooms in 2 cups (500 mL) boiling water until softened, about 5 minutes. Remove with slotted spoon; chop and set aside. Strain soaking liquid into measuring cup; add stock and enough water to make 3 cups (750 mL). Set aside.
In large shallow saucepan, melt 1 tbsp (15 mL) of the butter over medium heat; fry mushrooms, onion, garlic, thyme, salt and pepper, stirring occasionally, until onion is softened, about 5 minutes.
Add rice, stirring to coat. Add 1/3 cup vegetable stock; cook, stirring constantly, until no liquid remains. Add 1-1/2 cups (375 mL) of the stock mixture, 1/2 cup (125 mL) at a time and stirring after each addition, until completely absorbed, about 10 minutes.
Meanwhile, cook Arctic Gardens green beans in microwave at high for 1 minute, stirring once. Pat dry and cut into 1/4-inch (5 mm) pieces; add to rice mixture. Add remaining stock mixture. Stir in cheese, parsley and remaining butter.