In medium saucepan, combine rice, broth and water. Bring to boil; stir once or twice. Reduce heat; cover and simmer for 15 minutes or until rice is tender and liquid is absorbed.
In large skillet coated with cooking spray, cook onion, mushrooms and garlic. Stir in lemon juice and oregano. Add spinach, cheese, and pepper to rice; toss lightly until spinach is wilted. Garnish with roasted red peppers, if desired.