Step 1) MIX batter ingredients together in a greased 8 X 8-inch baking dish. Sprinkle with feta cheese and spinach. Sauté mushrooms and pepper strips in corn oil over medium-high heat for 2 minutes.
Step 2) TOP batter evenly with mushroom mixture. Sprinkle with mozzarella cheese and herbs.
Step 3) BAKE by placing in a cold oven. Set temperature to 350° F; bake for 30 minutes or until baked through.