Preheat oven to 375 degrees. Cut edges off onion, and remove outer layer. Cut onion into 1/2 inch wide slices, and separate into rings. Next, fill a small bowl (just large enough for onion rings to fit in) with Egg Beaters. Using a blender or food processor, grind Fiber One cereal to a breadcrumb-like consistency. Pour crumbs onto a small dish. One by one, coat each ring in egg and then crumbs (give each ring a shake after the egg bath). Place on an oven-safe baking dish sprayed with nonstick spray. Cook for 20-25 minutes, flipping rings over about halfway through. Serves one!