cooking.nytimes.com
A Spanish potato tortilla is an egg dish unlike any other. It doesn't resemble the French omelet, which is loose and wobbly. Nor is quite like an Italian frittata, which is puffy and custardy. Instead, a tortilla is a solid cake with just enough egg to bind the soft, sliced potatoes. The first step to making it is to gently cook sliced potatoes and onions in plenty of olive oil. And plenty means at least a cup, or maybe two. It sounds like a lot but most of it stays in the pan (and you can reuse it). Other than adding great flavor, the oil turns the potatoes velvety and luscious. Just make sure the heat is low enough so the potatoes and onions cook but don’t brown very much, though a few darkened spots are okay. In Spain, a tortilla is a tapas staple nibbled with drinks. But it’s also delightful for brunch, dinner or lunch, served either warm or at room temperature.