2 pounds large Yukon Gold potatoes, peeled, quartered, cut into ¼-inch slice
1 Onion, quartered, thinly sliced
2 ½ tsp. Kosher Salt
1 tsp. Black Pepper
Start by peeling and slicing your potatoes very thin. Use a mandoline if possible to ensure consistency in thickness of cuts. This helps ensure all potatoes will be cooked through in the end.
Add oil and heat skillet on medium. Cook the potatoes in small batches until tender without letting them brown for about 25 minutes.
Remove the potatoes from the oil and into a bowl.
In a separate bowl, beat the eggs until scrambled. Add egg, salt and pepper to potatoes. Fold the potatoes into the egg, being mindful not to allow egg to cook.
Heat about 3 tablespoons of oil in a skillet over medium-high heat. Add egg-potato mixture and cook for about 2 minutes, stirring constantly but gently to keep potatoes intact, until eggs begin to set (eggs will look scrambled). Spread mixture in an even layer; reduce heat to medium-low. Preheat broiler to high.
Continue cooking on low, shaking constantly, for about 10 minutes. Transfer skillet to oven and broil until top of tortilla is just cooked.
Remove from oven. Invert a large plate over skillet. Hold plate firmly over skillet and flip. Pair with tomato sauce or ketchup and serve warm or cold.
Add some chopped and fried bacon for texture and more flavor.