Caramelized onion quiche with lavender and crisped prosciutto
Instructions:
- CARAMELIZED ONIONS:
- 2½ pounds yellow onions (about 5 medium), cut in half through the root and sliced crosswise ¼ inch thick (10 cups);
- 1 teaspoon fine sea salt;
- 2 teaspoons packed light brown sugar;
- 1 tablespoon extra-virgin olive oil;
- 1 tablespoon unsalted butter (optional);
- 1 tablespoon white balsamic or red wine vinegar.
- PROSCIUTTO AND CUSTARD FILLING:
- 2 teaspoons extra-virgin olive oil;
- 4 ounces chopped prosciutto (about 1 cup);
- 2 large eggs;
- ½ cup plain whole-milk Greek yogurt;
- ¼ cup whole or lowfat milk;
- 1 ounce finely grated Gruyère cheese (about ½ cup);
- 1½ teaspoons dried lavender buds;
- 1 teaspoon dried thyme;
- ¼ teaspoon freshly ground black pepper;
-
, made with white whole wheat flour and partially baked in a 10-inch tart pan, preferably ceramic;- 1 tablespoon Dijon mustard.
- To prepare the caramelized onions, put the onions in a large colander set over a large bowl and sprinkle with the salt and sugar. Toss to combine and let sit for at least 10 minutes and up to 2 hours for the juices to draw, tossing a few times. Reserve the onion juices.
- Heat the olive oil in a large Dutch oven or a heavy-bottomed saucepan over medium heat until shimmering. Add the butter and wait until it melts and the foam almost subsides. Add the onions and cook, uncovered, stirring every 4 minutes or so until a brown sticky layer forms at the bottom and the onions start to brown at the edges, 25 to 30 minutes (decrease the heat a bit if the onions brown too fast). Add the onion juices, scrape the bottom of the pan to remove any browned bits, and cook for about 20 more minutes, stirring and scraping every minute or so, until the onions are golden and lightly caramelized. Stir in the vinegar and cook for 1 minute. Set aside to cool. You will have about 2 cups of onions.
- Position a rack in the center of the oven and preheat to 375°F.
- To prepare the prosciutto and the custard filling, heat the olive oil in a 10-inch skillet over medium heat until shimmering. Add the prosciutto and cook, stirring frequently, until crisp, 5 to 7 the prosciutto and cook, stirring frequently, until crisp, 5 to 7 minutes. Transfer the prosciutto to a plate. To make the custard, lightly beat the eggs with a fork in a 2-cup liquid cup measure or in a medium bowl. Add the yogurt, milk, cheese, herbs, and pepper and combine well. Place the tart pan with the crust on a large rimless baking sheet for easier handling. Brush the crust with the mustard and sprinkle with half the prosciutto crisps. Distribute the onions across the tart bottom and pour the custard mixture evenly on top.
- Carefully place the sheet with the tart pan in the oven (it can slide!) and bake until the top of the tart is lightly puffed and golden brown and the filling has firmed up, 45 to 50 minutes. Remove from the oven, carefully slide the tart pan onto a wire rack, and let sit for 15 minutes. Unmold (see sidebar), and cut into wedges, using a sharp serrated knife. Serve warm or at room temperature, sprinkled with the remaining prosciutto.
- TO GET A HEAD START: The caramelized onions, as in steps 1 and 2, can be prepared up to 5 days ahead. Chill, covered. The tart can be prepared completely 1 day ahead. Allow to cool to room temperature, cover loosely with plastic wrap, and chill. Bring to room temperature before serving, or warm in a 325 F oven for 15 to 20 minutes.
- TO LIGHTEN IT UP: You can use lowfat or nonfat Greek yogurt.
- TO MAKE IT VEGETARIAN: Omit the prosciutto. In step 4, add ¼ teaspoon salt to the custard. Sprinkle the crust with ½ cup crumbled blue cheese (2 ounces) before adding the onions.