Caramelized Onion and Apple Tarts with Gruyere
- 2 tablespoons olive oil
- 3 medium sized sweet yellow onions, halved and thinly sliced
- Kosher salt and freshly ground black pepper
- 2 tablespoons butter
- 2 tart apples, peeled, cored and sliced thin
- 1 teaspoon granulated sugar
- 2 cups shredded Gruyère cheese
- 2 tablespoons minced scallions
- 1 teaspoon chopped fresh thyme
- 1 package frozen puff pastry dough, thawed
- 1 egg, beaten
- 2 tablespoons water
Adapted from smokymountaincafe.blogspot.com
In a large skillet over medium heat, warm up the oil. Add the onions and sprinkle with about 1 teaspoon salt and saute, stirring occasionally, until the onions begin to carmelize, about 20-25 minutes. Transfer to a large bowl and aloow the onions to cool.
Place your oven racks, one in the upper third and the other in the lower third of an oven. Preheaoven to 400 degrees F. Line 2 baking sheets with parchment paper.
In the same skillet over medium heat, melt the butter. Add the apples and sprinkle with the sugar and stir to coat the apples. Saute, stirring, until the apples are just starting to caramelize and have softened, about 10 minutes.
Transfer to the bowl with the onions and stir in the cheese, chives, thyme and a dash of pepper.
Cut the puff pastry into 2-inch squares and place on the prepared baking sheets. Space the squares about 1 inch apart. I used a flutes pastry cutter, thinking the pastry would look really pretty once it was baked. When it was all said and done, the edges were smooth, but it helped me cut them evenly.
Slightly beat the egg and blendin the 2 tablespoons of water. Brush the egg mixture on each pastry square.
Place 1 heaping tablespoon of the filling in the center of each square. Season with salt and pepper.
Bake, rotating the baking sheets from top to bottom and front to back halfway through baking, until the pastry is crisp underneath and golden brown on top, about 25 minutes. When you rotate the pans, the pastry make seem to deflate a little bit, but don't worry, your tarts will be just fine.
Transfer the baking sheets to wire racks and let the tarts cool to room temperature. Serve at room temperature.