preheat oven to 300 degrees fahrenheit
spray springform pan with pan spray
toss potatoes with olive oil, season with salt and pepper to your liking (small amounts)
saute potatoes in saute pan on medium-high heat until slightly colored and tender, don't overcook about 15 to 20 minutes. Or layered in springform pan with onion on top, cook at 425 for 30 minutes. Reduce heat to 300.
Add potatoes into springform pan if you saute potatoes first,
top with eggs, spread evenly over the layered potato and onion
cook in 300 degree oven for 30 minutes or until egg is set on top, (slightly springy, not runny)
with a knife, go around the edge of the springform pan releasing the egg from the side of the pan, unclasp the spring and open the pan, remove outer walls of pan. Slice Spanish tortilla into wedges