Spray skillet with Pam along with enough oil to cover bottom of pan. Saute cut up sausage, potatoes and onion until sausage and potatoes cooked well. Sprinkle parsley and pepper on mixture. Cook over medium heat turning often so sausage and potatoes do not stick to pan. Beat 12 eggs in large bowl. Add grated Parmesan cheese.
Lower heat to sausage mixture in pan (very low). Add egg mixture in gradually and gently, spreading evenly in pan. Sprinkle remaining parsley on top of omelet. Cook very slowly, on sides of pan. Preheat broiler, put omelet under broiler observing constantly, will brown and become bubbly on top of omelet. When top is cooked remove from broiler. Stick toothpick into omelet, if clean omelet is done. If toothpick has egg on it continue to cook on very low heat until toothpick comes out clean. Takes about 1 hour to complete. Cool 15 minutes. Remove gently from pan.
