Caramelized Onion Quiche

Heat the oven (with the oven rack in the lowest position) to 375°F.

For the crust, in a food processor, combine the flour and salt. Add the butter and pulse several times in short, quick pulses until the butter pieces are pea-size. Then add 3 tablespoons ice water. Pulse a few times just to incorporate the water (you don’t want to overmix). The dough should look like moist crumbs and hold together when pinched. If it’s a bit dry and doesn’t hold together, add another tablespoon of ice water and pulse twice.

Turn out the dough onto a lightly floured work surface. Gather up the crumbs and knead a few times until the dough comes together. Shape into a 1-inch-thick round disk.

Pressing evenly, roll the dough out into a large ¼-inch-thick circle, occasionally rotating it to help keep its round shape (sprinkle with a little more flour, both on top and underneath, if the dough starts to stick).

Lay the dough into a 9½-inch fluted tart pan with a removable bottom. Gently press the dough into the cor­ners. Fold the overhanging dough back inside and press to seal (the top of the crust should be just a little higher than the pan). Refrigerate while you make the filling.

For the filling, thinly slice the onions. In a large skillet over medium-high heat, heat the oil and butter. Add the onions and ½ teaspoon of the salt. Cook, stirring occasionally, for 5 to 6 minutes, until they start to soften. Stir in the thyme. Reduce the heat to medium and continue to cook the onions, stirring often, for another 15 to 20 minutes, until caramelized. Let cool.

In a medium bowl, whisk together the eggs. Whisk in the half and half, pepper, and the remaining ½ teaspoon salt. Stir in the cheese and onions.

Pour in the filling, making sure the onions are evenly spread. Bake for 50 to 60 minutes, until the filling is puffed and set in the mid­dle and the crust is golden brown. Serve warm or at room temperature.