Caramelized Onion Quiche

01Method

1. 1

   Prepare the crust: Roll out the dough on a lightly floured surface into a 12-inch round. Press it into a 9 x 1½-inch tart pan or pie dish, building up the edges slightly to account for shrinkage. Place in the freezer for 30 minutes to firm up.

2. 2

   Preheat the oven to 350°F. Line the chilled pastry shell with aluminum foil, pressing it firmly into the edges and leaving excess foil hanging over the sides as handles. Fill at least two-thirds of the shell with pie weights, dried beans, or uncooked rice.

3. 3

   Blind-bake the crust with weights for 15 minutes, then remove from the oven and allow to cool briefly. Lift out the foil and weights carefully using the overhanging foil as handles.

4. 4

   Prick the base of the pastry all over with a fork, then return to the oven and bake for a further 10 minutes until lightly golden. Transfer to a wire rack while you prepare the filling.

5. 5

   Caramelize the onions: Warm the olive oil in a large heavy-bottomed skillet over medium heat. Add the sliced onions and season lightly with salt. Cook, stirring occasionally, for about 10 minutes until softened and translucent. Lower the heat to medium-low and continue cooking for 40 minutes, stirring from time to time, until deeply browned. Stir in the balsamic vinegar and cook for another 10 minutes until fully caramelized. Remove from heat.

6. 6

   Begin assembling: Set the tart pan on a baking sheet. Scatter half the Gruyère evenly over the base of the crust, spread the caramelized onions on top, then cover with the remaining cheese.

7. 7

   Make the custard: Whisk together the milk, cream, and eggs in a bowl. Season with nutmeg, salt, and pepper. Pour the mixture evenly over the filling in the tart.

8. 8

   Bake the quiche at 350°F for 30 to 35 minutes, until the center is just set. Let it rest on a wire rack for 10 to 15 minutes before slicing and serving.