Prepare an oven tray with parchment paper or aluminum foil
Peal potatoes, dice them and place them on a bowl.
Coat them with some salt and olive oil. Toss to mix well.
Place the potatoes on the oven tray and bake for 15-20 minutes.
In the meantime, whisk the eggs in a large bowl, add salt, paprika and oregano to taste.
If you'd like to add spinach, wash it and add it to the egg mix now.
Once the potatoes are done, remove from the oven and place them in the bowl with the eggs mixture. Toss to combine all.
Heat up a large skillet to medium-high heat. Coat it with a bit of olive oil.
Pour the egg and potato mixture and let it cook to medium heat. IT will take about 20-25 minutes to cook. You can cover it so that the egg on top cooks better.
Once most of the egg is cooked, flip it to finish cooking on the top. To flip, you can cover the skillet, flip it with the cover so the tortilla comes out, and then place it in the skillet again. Cook for 10-15 more minutes.