Whisk the eggs together in a medium bowl and add salt and pepper to taste. Grate the cheese. I just had some of the Mexican blend around otherwise I would have just used Jack or Cheddar.
Heat the butter in a 10 inch skillet over medium heat. When it has melted, tilt the pan so the butter has coated the bottom well. Then pour in the eggs.
Cook slowly until the bottom has begun to set. Tilt the pan and lift the set eggs to let the runny ones run under the set part. Continue until the eggs are still wet on the top, but not too runny. Add the cheese, salsa, and sour cream to half the eggs, then fold the other half over onto the top. Cook another minute or two until firmly set.
Cut the omelet in half and serve with some toast. French bread is fantastic but any buttered toast will do.