1large waxy potatosuch as white, red, or Yukon Gold, peeled, quartered, and thinly sliced
1onionquartered and very thinly sliced
½teaspoondried thymeoregano, or basil, or 1 teaspoon chopped fresh thyme, oregano, or basil
Kosher salt and freshly ground black pepperto taste
10large eggs
¼cupcoarsely chopped fresh Italian flat-leaf parsleyor basil (optional)
½cupshredded or crumbled cheesesuch as cheddar, provolone, Monterey Jack, mozzarella, feta, Parmesan, or goat cheese
Instructions
Preheat the broiler with the rack set about 4 inches away from the heat source.
Melt the butter over medium heat in a medium-size (10-inch) broiler-proof skillet. Add the potato, onion, and the 1⁄2 teaspoon of dried thyme, oregano, or basil, if using, and season with salt and pepper to taste. Cover the skillet and cook the potato and onion until they are beginning to become tender, about 10 minutes, stirring occasionally. Reduce the heat if it seems like the vegetables are starting to burn. Uncover the skillet and cook the vegetables until they are tender and turning golden, about 4 minutes longer.
Meanwhile, place the eggs, parsley, and 1 teaspoon of fresh thyme, oregano, or basil, if using, in a medium-size bowl and whisk to combine well. Season the egg mixture with salt and pepper to taste. When the vegetables are ready, pour the eggs into the skillet and stir to combine everything. Let the frittata cook until the eggs start to set on the bottom. Reduce the heat to medium-low and, using a spatula, gently lift the edge of the frittata so that the uncooked eggs run underneath those that are set on the bottom. Do this every couple of minutes until the frittata is pretty much set on the bottom but the top and middle are still a bit runny.
Sprinkle the cheese over the top of the frittata and place the skillet under the broiler. Broil the frittata until it is set, the cheese is melted, and the whole top is lightly golden, 2 to 4 minutes. Remove the skillet from the broiler and let the frittata sit for a minute or two on a heatproof surface. Leave a dishtowel draped over the handle of the skillet to remind yourself that the handle is hot!
Run a spatula or knife around the edge of the skillet to loosen the frittata. You can cut it into wedges and serve it directly from the skillet. Or carefully slide the whole thing onto a serving plate, using a spatula to help guide the frittata out, then cut it into wedges.