The most unexpected thing about a tortilla is that, unlike many egg dishes, you don't have to eat it right away. It will be delicious the next day if you warm it up. If you are very fond of cheese, before putting the tortilla in the oven, you can lightly scatter your favourite cheese over it, or simply add grated cheese to the egg mixture - " You can never have too much of a good thing."
If you don't have a frying pan that can be put in the oven, you can cook the tortilla on the stove. When it's done on one side, cover the pan with a kitchen board and gently turn the tortilla onto it. Slowly slide the tortilla off the board, back to the frying pan and cook for a further 3-4 minutes over medium heat.