Wash and chop vegetables and sausage. Set aside.
Heat a large non-stick or cast iron skillet over medium heat. When hot, add butter to pan.
Pour eggs into the skillet and coat the bottom of the pan.
When the eggs are partially set, scrape the edges and tip the pan so that the uncooked egg at the top can spread to the hot cooking surface of the skillet.
Now add the veggies and sausage to one half of the omelet and continue to cook until the egg is almost fully set.
Using a spatula, fold the empty half over top of the vegetables and sausage. Cook for 2 minutes longer, then serve.
Garnish with sliced avocado