1. Crack the eggs into a mixing bowl, add salt and pepper, and whisk until well combined.
2. Heat the butter in a non-stick skillet over medium heat.
3. Add the chopped bell peppers, onions, and tomatoes to the skillet and sauté for 2-3 minutes.
4. Pour the whisked eggs into the skillet and let it cook for 2-3 minutes until the edges start to set.
5. Sprinkle the shredded cheese on one half of the omelet and fold the other half over the cheese. Cook for another 1-2 minutes until the cheese melts.