A spinach and mushroom omelette is a quick and healthy breakfast option. Heat some oil or butter in a non-stick skillet over medium heat. Add sliced mushrooms and cook until they are tender. Add a handful of fresh spinach leaves and cook until wilted. In a separate bowl, whisk together eggs, salt, and pepper. Pour the egg mixture over the mushrooms and spinach in the skillet. Cook the omelette until the eggs are set, then fold it in half. Serve the omelette with a side of whole grain toast or fresh fruit for a balanced and nutritious meal.