Caramelized Onion Quiche

Instructions

1. Prepare the crust
   In a food processor, combine flour and salt. Add the cold butter and pulse until the mixture resembles coarse crumbs. Gradually add ice water and pulse until the dough just comes together. Form into a disk, wrap in plastic, and refrigerate for at least 30 minutes.
2. Caramelize the onions
   Heat olive oil and butter in a large skillet over medium-low heat. Add the sliced onions and cook, stirring occasionally, for about 40-45 minutes until deeply golden brown. Add thyme leaves and brown sugar in the last 5 minutes. Season with salt and pepper.
3. Roll and blind bake the crust
   Preheat oven to 375°F (190°C). Roll out the chilled dough on a floured surface and fit into a 9-inch tart pan. Trim excess dough, prick the bottom with a fork, line with parchment paper, and fill with pie weights. Bake for 15 minutes, then remove weights and parchment and bake for another 5-7 minutes until lightly golden.
4. Prepare the filling
   In a large bowl, whisk together eggs, heavy cream, and milk until well combined. Stir in grated Gruyère cheese, nutmeg, salt, and pepper.
5. Assemble the quiche
   Spread caramelized onions evenly over the bottom of the par-baked crust. Pour the egg mixture over the onions, ensuring it's evenly distributed.
6. Bake the quiche
   Bake at 350°F (175°C) for 35-40 minutes, until the center is set but still slightly jiggly and the top is golden brown. A knife inserted near the center should come out clean.
7. Cool and serve
   Allow the quiche to cool for at least 15 minutes before removing from the tart pan. Serve warm or at room temperature with a simple green salad on the side.