Whip eggs with sour cream. Set aside. In omelette pan, saute mushrooms, spinach, and green onion in olive oil, 5-8 minutes. Pour eggs in pan. Use spatula to evenly distribute veggies. Once eggs are cooked on bottom, flip. Add tomato and cream cheese to the cooked side. Seal tomato and cream cheese in the omelette by folding in half with spatula. Flip until fully cooked. Serve topped with avocado slices. Season with salt and pepper to taste.