Start with potatoes. Slice them, and then julienne them. One could push this idea even further and make shoe string fries. I may try that in the future.
Good french fries are actually moderately difficult to make. You want to fry them twice. You fry them once in medium hot oil. This is known among fry masters as "blanching" the potatoes. Blanching the potatoes forces some of the starch out. When you remove your fries from the oil, they should be limp but not golden brown. The fries pictured above are actually on their second frying. The exuded starch on the outside of the fries will caramelize during the second, high heat frying, which will result in a crispy and colorful french fry. Salt your french fries as soon as you remove them from their second frying.
These are the fries that I added to the beaten eggs. I ate one or two of them to see if they were any good. They were.
The fries are salty, but you'll also want to salt the beaten eggs. Eggs taste very good when properly salted. When under-salted, they aren't all that tasty.
You'll want to put quite a generous amount of olive oil into the seasoned cast iron skillet before adding the eggs and fries mixture. If you want, you can start cooking the eggs on the stove top, on low heat, before putting the whole mess into a low oven, like 250 degrees. In Spain, tortillas may be traditionally cooked entirely on the stove top, not in the oven. The secret is low heat. You do not want to burn the eggs. The other secret is that bit about a generous amount of olive oil. When you put the egg mixture into the skillet, the oil should come up around the sides and pool on top.
This is the finished french fry frittata or tortilla español. Let it come to room temperature before eating it. It's better that way. You can also chill it. I cut a slice of this one and put it into a baguette from Woodstar cafe. I buttered the bread and spread a small amount of ketchup on the bread. It was good.