Heat oil in a pan. Saute mushroom until soft.
Add salt, pepper, crushed garlic, onions. Saute for 2-3 mins.
Add spinach, evaporate excess water. Saute till all water is evaporated.
Beat the eggs in a bowl, add milk. Add the spinach and mushroom mixture to the eggs.
Heat a flat pan, add oil. When the pan is ready, pour the egg mixture and tilt the pan until the egg mixture has evenly spread in the pan. Cook on medium heat for 3-5 mins.
When its cooked from one side, loosen the edges of the omelette and flip it carefully. Now cook the other side for 2-3 mins until its brown.
Broil the omelette in oven for 2-3 mins until top layer is crispy brown.
Cut into triangles. Serve hot!