A Spanish tortilla is a deceptive thing. How can a mix of potatoes, onion, and eggs taste so perfect? Any yet, like anything rooted in simplicity, the answer is in the ingredients and the technique. In this casserole, inspired by the classic Spanish tortilla, all the signature flavors are present — from the garlicky, olive oil-slicked potatoes and onions to the tender egg filling. The technique, however, has changed. Instead of the task of frying and flipping the tortilla in a cast iron pan (a sometimes perilous, if worthwhile, task). you'll make this dish in your trusty casserole pan.
It comes out of the oven with impressive puffed-up edges before settling into the baking dish. And like its namesake inspiration, this casserole is just as delicious — if not more so — at room temperature or even when pulled straight from the fridge than it is hot out of the oven.
Give the Potatoes a Head Start in the Oven
Thin rounds of tender, garlicky potatoes are key to this Spanish tortilla–inspired casserole. The recipe relies on Yukon gold potatoes, which are good all-purpose spuds with a medium starch content that can be counted on to hold their shape when cooked. Since the potatoes benefit from extra time in the oven, they're first tossed with a drizzle of oil and thin slivers of onion, and cooked just until they lose their firmness. It's only then that the eggs are added to the baking dish and the whole thing goes back into the oven for round two of cooking so you finish with tender potatoes and just-set eggs.
Easy Spanish Tortilla Casserole
Serves 6 to 8
Yukon Gold potatoes (about 6 medium), peeled and thinly sliced
yellow onion, thinly sliced
2 1/2 tablespoons
olive oil, plus more for the baking dish
kosher salt, divided
freshly ground black pepper
whole or 2% milk
finely chopped chives
Arrange a rack in the middle of the oven and heat to 375°F. Coat a 9x13-inch baking dish with a thin layer of olive oil; set aside.
Place the potatoes, onion, oil, garlic powder, 1/2 teaspoon of the salt, and pepper in a large bowl and toss to evenly combine. Transfer to the prepared baking dish and spread into an even layer. Bake until the potatoes are almost fork-tender, about 20 minutes.
Whisk the eggs in a large bowl until the whites and yolks are completely mixed and the eggs are a bit frothy. Add the sour cream, milk, garlic, and remaining 1/2 teaspoon salt, and whisk to combine. Pour over the potatoes.
Bake until the top is light golden-brown and a knife inserted in the middle comes out clean, about 35 minutes. Let cool for 5 minutes before sprinkling with the chives and serving warm or at room temperature.
Storage: Leftovers will keep for up to 4 days stored in an airtight container in the refrigerator.