Step 1: Prepare the Filling : Heat olive oil or butter in a skillet over medium heat. Add garlic and sauté for 30 seconds until fragrant. Add mushrooms and cook for 3–4 minutes until softened and lightly browned. Add spinach and cook until wilted, 1–2 minutes. Remove from heat and set aside.

Step 2: Prepare the Eggs : In a bowl, whisk eggs with milk or cream, salt, and pepper until smooth and slightly frothy.

Step 3: Cook the Omelette : Heat butter in a non-stick skillet over medium-low heat. Pour in the egg mixture and let it set for 1–2 minutes without stirring. Gently lift the edges with a spatula, tilting the pan to let uncooked egg flow underneath. When eggs are mostly set but still slightly creamy, add the spinach and mushroom mixture on one half. Sprinkle shredded cheese over the filling.

Step 4: Fold and Serve : Carefully fold the omelette in half over the filling. Cook for another 1–2 minutes until cheese is melted and eggs are fully set. Slide onto a plate and garnish with fresh herbs if desired.