Makes 6 servings
A frittata is a dish that every cook should know how to make, partly because it’s so delicious, partly because it’s so easy and partly because it’s so versatile — it’s a happy home for tidbits of all sorts. That it can be made ahead and served at room temperature is a bonus. Essentially an omelet that’s cooked for a couple of minutes on the stove and then quickly finished in the oven, a frittata can be made with everything you’d normally put into an omelet, but there’s no folding and crossing your fingers that it all holds together. Because I make frittatas so often, and because they’re always different, depending on what I’ve got on hand, it was hard for me to come up with a “real” recipe. This may sound odd to you now, but a couple of frittatas later, you’ll be saying the same thing (see the Kale and Onion Frittata).
This version takes its inspiration from a diner standard: the Western omelet, sometimes called a Denver. It’s got onions, bell peppers and some minced jalapeño, as well as chile powder and hot sauce. The original has ham, and you can add that — or bacon or pancetta — if you want to. I like sliced tomato and cheese on this and many other frittatas, but you can leave the top bare or go for scallions or leeks, pepper rings or thin rounds of onion.
a word on spring onions
Spring onions (sometimes marketed as Texas onions) look like large scallions. They have scallion-like greens, but their base is a bulb, like a regular onion. Spring onions are milder and sweeter than normal onions. You can substitute scallions — you’ll need three or four for each spring onion — or an onion.
Center a rack in the oven and preheat it to 350 degrees F.
Pour the oil into a 9-inch cast-iron or other ovenproof skillet and place the pan over medium heat. Add the onion, bell pepper and jalapeño, season with the chile powder and some salt and pepper and cook, stirring frequently, until the vegetables are moderately soft, about 5 minutes.
Whisk the eggs together with some salt, pepper and chile powder and as much hot sauce as you’d like — keep in mind that you can always season the frittata with more hot sauce after it’s baked. Pour the eggs over the vegetables in the skillet and stir just to blend, then let the eggs cook, undisturbed, for 2 minutes. Top with the tomato, sprinkle with the cheese, toss on a sprig or two of the thyme, if you’re using it, and slide the pan into the oven.
Bake the frittata for 8 minutes. If you want to serve the frittata in the pan, look at it now. If the sides are puffed and firm, and only the center jiggles a little bit, remove it from the oven (the frittata will continue to cook after it comes from the oven, so as long as you don’t want to unmold it, it’ll be fine). If you want to turn the frittata out onto a plate, let it bake for another 3 to 4 minutes. If you want a little more color, run the frittata under the broiler for a couple of minutes. Transfer the frittata to a rack and let it rest for 10 minutes.
If you are going to unmold the frittata, have a cutting board and a serving platter at hand. Run a flexible heatproof spatula around the edges of the frittata, working the spatula under it a bit as you go. Carefully (the pan is heavy . . . and hot!) turn the pan over onto the cutting board; lift off the pan. If anything sticks, see if you can lift it out of the pan and replace it; if not, forget about it. Turn the frittata onto the serving plate (repositioning any tomatoes that have come loose, as they’re bound to), sprinkle with additional thyme, if desired, and cut into squares or wedges.
Serve the frittata while it’s warm, or allow it to come to room temperature.
Storing: The frittata is best the day it is made, but leftovers can be covered and refrigerated for up to 1 day.
Instead of the onion, pepper and chile powder, cook ¼ pound kale, trimmed and shredded (or use leaves of baby kale), 3 medium spring onions or other onions, halved and thinly sliced, and 3 garlic cloves, minced, in the oil. Whisk 3 tablespoons Dijon mustard into the eggs, and proceed as directed. You can swap the kale for mustard greens, spinach or chard or add these to the kale. Also think about adding sliced zucchini or mushrooms, chopped bacon or shrimp, or even shreds of leftover chicken or pork — just remember that whatever you put into a frittata has to be cooked first.