Frittatas with caramelized onions have long been a favorite of mine. What makes them special is the wash of melted butter and vinegar sauce spooned over the finished dish. It’s made in the pan in just a few seconds. This recipe calls for half the onion mixture on page 176 in a three-egg frittata. You can serve it whole or cut it into squares, pile it on crackers or bread, and serve as an appetizer.
CARAMELIZED ONION FRITTATA WITH SHERRY VINEGAR
Makes 2 thin frittatas or 1 larger, thicker one
3 eggs Sea salt and freshly ground pepper 1 tablespoon chopped parsley
Caramelized Onions with Vinegar and Cloves (see below)
5 teaspoons butter
Parmigiano-Reggiano, for grating 11⁄2 tablespoons sherry vinegar
Whisk the eggs with a few pinches of salt and some freshly ground pepper, then stir in the parsley and the caramelized onions. Heat your broiler.
Melt 2 teaspoons of the butter in a 10-inch skillet until it’s sizzling, then add the eggs and lower the heat. Cook the eggs, covered, until they are set and golden on the bottom, about 6 minutes for a thin frittata, longer for a thick one.
Grate a little of the cheese over the top, then slide the pan under the broiler to finish cooking. The top should be light gold and firm. Loosen the frittata and tilt it onto a plate, then return the pan to the stove and raise the heat.
Add the remaining butter to the pan and when it begins to foam, add the sherry vinegar. Slide the pan back and forth to emulsify the two. Stand back! The vinegar fumes are strong. When you have a sauce, pour it over the frittata and serve.
Caramelized Onions with Vinegar and Cloves
3/4 pounds white or yellow onions
3/4 tablespoons olive oil
½ to 1 tablespoon sherry vinegar
Sea salt and freshly ground pepper
1⁄16 teaspoon ground cloves
Peel the onions and halve them lengthwise, then cut each half into thirds or quarters. Slice each piece crosswise about 1⁄4 inch thick. (Do this if you’re using the onions in a frittata—the even slices will keep it looking nice when you cut into it. If this isn’t important, just slice the halves into long pieces.)
Warm the olive oil in a 10-inch skillet, add the onions, and cook over medium heat, stirring occasionally until they begin to color. Reduce the heat to medium-low, cover the pan, and continue to cook, stirring occasionally, until they’ve started to color, about 20 minutes. Remove the lid and stir frequently, keeping an active eye on them to make sure they don’t burn.
When they’re limp and caramel colored, raise the heat, add the vinegar and let it reduce. Season with ¼ to ½ teaspoon of salt, lots of freshly ground pepper, and the cloves. Taste, and if you want a little more vinegar, add it—carefully. Sherry vinegar is strong. You can use the onions right away or refrigerate for several days.
Excerpt from In My Kitchen by Deborah Madison. ©Deborah Madison 2017. Ten Speed Press, an imprint of the Crown Publishing Group.