Spinach and Mushroom Omelette with Avocado

1. In a medium bowl, whisk the eggs until well beaten. Season with a pinch of salt and pepper. 2. Heat olive oil in a non-stick skillet over medium heat. 3. Add the onions and bell pepper to the skillet. Sauté for 2-3 minutes until softened. 4. Add the mushrooms and cook for another 2 minutes until they start to soften. 5. Add the spinach and cook until wilted, about 1 minute. 6. Pour the beaten eggs over the vegetables in the skillet. 7. Cook the eggs without stirring for about 3-4 minutes until the edges start to set. Then gently lift the edges to allow uncooked eggs to flow underneath. 8. When the eggs are almost set, fold the omelette in half and cook for another minute until fully set. 9. Transfer the omelette to a plate and serve with sliced avocado on the side.