Preheat: Preheat the oven to 180 degrees Celsius (350 degrees Fahrenheit).
Saute Spinach: In a frying pan, heat the olive oil and saute the spinach until it wilts, then set it aside for now.
Mix Ingredients: In a mixing bowl, beat the eggs and add in the sauteed spinach and smoked salmon.
Bake: Pour the mixture into a baking dish and place in the oven for approximately 30 minutes or until the eggs are set.
Serve: Once cooked, let the frittata cool slightly before cutting into portions. It can be served warm or at room temperature.