PREPARATION:

1. Bring 4 cups water to a boil in medium saucepan over high heat. Slowly add cornmeal to water, stirring constantly with wire whisk. Reduce heat to low; stir in marjoram. Simmer 15 to 20 minutes or until polenta thickens and pulls away from side of saucepan. Spread on 13X9-inch ungreased baking sheet. Cover and chill about 1 hour or until firm.
2. Heat oil in medium nonstick skillet over medium heat. Cook and stir mushrooms, leeks and garlic 5 minutes or until vegetables are crisp-tender. Stir in mozzarella, basil, oregano and black pepper.
3. Place bell peppers and remaining 1/4 cup water in food processor or blender; cover and process until smooth. Preheat oven to 350°F. Spray 11X7-inch baking dish with nonstick cooking spray.
4. Cut cold polenta into 12 (3-1/2-inch) squares; arrange 6 squares in bottom of prepared dish. Spread with half of bell pepper mixture, half of vegetable mixture and 2 tablespoons Parmesan. Place remaining 6 squares polenta over Parmesan; top with remaining bell pepper and vegetable mixtures and Parmesan. Bake 20 minutes or until cheese is melted and polenta is golden brown. Cut into 6 wedges before serving.