Upside Down Caramelized Leek Tart
This is a great dish for a light, al fresco Spring dinner!
1 - 14 ounce package frozen puff pastry, thawed (or pie crust)
6 leeks, root ends and dark green parts removed, cut in half lengthwise
2 tablespoons pure olive oil
1/4 cup champagne vinegar (or whatever vinegar you have)
2 tablespoons unsalted butter
1 teaspoon sugar
1 teaspoon fresh thyme, picked and chopped
2 tablespoons Dijon mustard
1/2 cup grated Parmesan (or cheese of your choice)
kosher salt and freshly ground black pepper to taste
In a mixer, combine the butter and sugar. Add the flour, cornstarch and salt. Press into a baking dish and prick with a fork. Sprinkle with turbanado sugar and bake at 350 until browning on the edges (somewhere around 20+ minutes). Once cool, break into random shapes.Preheat oven to 400 degrees. Roll out puff pastry on a lightly floured surface to a 12" square. Cut to size of your skillet - 10 inches for mine. Prick and place on baking sheet in your refrigerator. Toss leeks in oil and sprinkle with kosher salt and pepper and place on another baking sheet. Arrange leeks, cut sides down, and roast until tender and lightly browned in spots (about 20 minutes). Let cool. Remove tough, leathery outer layer, then transfer leeks to a cutting board.
Meanwhile, in your skillet, bring the vinegar to a simmer over medium-high heat. Add the butter, sugar and thyme until the butter has melted (about 2 minutes). Remove from the heat and let cool slightly. Arrange the leeks, cut sides down and side by side in rows, in the vinegar butter mixture. Brush the leeks with mustard. Sprinkle with the Parmesan cheese.
Drape the chilled pastry over the leeks, tucking the edges inside the skillet. Cut three 3"-long slits into the pastry (cutting all the way through to let steam escape). Bake the tart until the pastry is deeply golden brown and puffed (about 35-45 minutes). Let the tart cool slightly, about 5 minutes. Carefully place a large plate on top of the skillet. Invert the tart onto the plate. If any of the leeks get left behind in the skillet, just scoop them back into the tart.