Place a large skillet over medium heat.
Add butter and melt. Do not burn.
Add onions and green pepper. Cook, stirring, until soft and fragrant. Remove from skillet to a small bowl. Do not clean skillet. Set aside.
In a mixing bowl, add eggs, water and salt. Beat to mix well.
Return skillet to medium heat.
Pour in egg mixture. Allow to cook for just a bit.
Add prepared onions and peppers, scattering to cover cooking egg mixture.
Add tomatoes, bacon, ham, sauce, roast beef and 1/2 cup of cheese.
When egg is almost cooked, fold omelet in 1/2. Top with remaining cheese.
Carefully remove from pan to serving plate.
Sprinkle with green onion.
Serve hot with salsa and sour cream.