Heat oven to 350 degrees F. Coat a baking sheet with vegetable cooking spray. In a small saucepan, bring water to a boil. Stir in instant brown rice and salt. Return to a boil; reduce heat and simmer, covered, for 5 minutes. Meanwhile, in small skillet, heat olive oil and diced onion over medium-high heat, and cook until onion is soft, about 4 minutes. Stir in minced garlic and Italian seasoning; cook 1 minute more. Place fresh spinach in a bowl, microwave 2 minutes, then chop. In large bowl, combine cooked rice, onion mixture, and spinach. Stir in egg, shredded mozzarella, and Parmesan cheese. Place heaping tablespoons on baking sheet; shape into rectangles. Bake 20 minutes.