1. Preheat oven to 425°F. Coat 8-inch square baking pan with nonstick cooking spray. Layer tomatoes in bottom of pan and sprinkle with 1/3 cup French Fried Onions.
2. Combine 1 cup onions and remaining ingredients in medium bowl; mix just until dry ingredients are moistened. Pour over tomato layers. Bake 30 minutes or until toothpick inserted in center comes out clean. Cool 15 minutes; invert onto serving plate. Serve warm with tossed green salad.